diff --git a/app/src/main/rust/stores/src/amazon/install/mod.rs b/app/src/main/rust/stores/src/amazon/install/mod.rs
index 113814145..ff35d45e5 100644
--- a/app/src/main/rust/stores/src/amazon/install/mod.rs
+++ b/app/src/main/rust/stores/src/amazon/install/mod.rs
@@ -248,8 +248,10 @@ fn cleanup_obsolete(
     old: &[GameFile],
     new: &[GameFile],
     cancel: &AtomicBool,
+    gate: &ReplaceGate,
+    ev: &dyn Events,
     log: &dyn Fn(&str),
-) -> bool {
+) -> Result<bool, Stop> {
     let key = |path: &str| -> Option<String> {
         let normalized = manifest::check_path(path).ok()?;
         Some(normalized.to_lowercase())
@@ -265,23 +267,23 @@ fn cleanup_obsolete(
     };
     let Some(old_keys) = inventory(old) else {
         log("obsolete Amazon files preserved: old inventory contains unsafe or case-colliding paths");
-        return cancel.load(Ordering::Relaxed);
+        return Ok(cancel.load(Ordering::Relaxed));
     };
     let Some(new_keys) = inventory(new) else {
         log("obsolete Amazon files preserved: target inventory contains unsafe or case-colliding paths");
-        return cancel.load(Ordering::Relaxed);
+        return Ok(cancel.load(Ordering::Relaxed));
     };
     let _ = old_keys;
     let Ok(root) = game_dir.canonicalize() else {
         log("obsolete Amazon files preserved: install folder could not be resolved");
-        return cancel.load(Ordering::Relaxed);
+        return Ok(cancel.load(Ordering::Relaxed));
     };
     let mut removed = 0usize;
     let mut preserved = 0usize;
     for file in old {
         if cancel.load(Ordering::Relaxed) {
             log("obsolete Amazon cleanup cancelled; remaining files were preserved");
-            return true;
+            return Ok(true);
         }
         let Some(k) = key(&file.path) else { preserved += 1; continue };
         if new_keys.contains(&k) { continue; }
@@ -308,10 +310,17 @@ fn cleanup_obsolete(
             preserved += 1;
             continue;
         }
+        if !gate.allow(ev) {
+            return Err(Stop::Failed(REPLACE_REFUSED.into()));
+        }
+        if cancel.load(Ordering::Relaxed) {
+            log("obsolete Amazon cleanup cancelled; remaining files were preserved");
+            return Ok(true);
+        }
         if fs::remove_file(&canonical).is_ok() { removed += 1; } else { preserved += 1; }
     }
     log(&format!("obsolete Amazon cleanup removed={removed} preserved={preserved}"));
-    cancel.load(Ordering::Relaxed)
+    Ok(cancel.load(Ordering::Relaxed))
 }
 
 pub fn run(req: &Request, cancel: &AtomicBool, ev: &dyn Events) -> Result<Finished, Stop> {
@@ -466,7 +475,7 @@ pub fn run_download(
     let stats = result?;
 
     let cleanup_cancelled = if let Some(installed) = installed_manifest.as_ref() {
-        cleanup_obsolete(&req.game_dir, &installed.files, &manifest.files, cancel, &log)
+        cleanup_obsolete(&req.game_dir, &installed.files, &manifest.files, cancel, &gate, ev, &log)?
     } else {
         ev.log("obsolete Amazon files preserved: no retained prior manifest is available");
         cancel.load(Ordering::Relaxed)
diff --git a/app/src/main/rust/stores/src/amazon/install/tests.rs b/app/src/main/rust/stores/src/amazon/install/tests.rs
index 2e40ce79b..e4a0d2419 100644
--- a/app/src/main/rust/stores/src/amazon/install/tests.rs
+++ b/app/src/main/rust/stores/src/amazon/install/tests.rs
@@ -350,7 +350,7 @@ fn obsolete_cleanup_removes_only_unchanged_prior_manifest_files() {
     ];
     let new = vec![GameFile { path: "current.bin".into(), size: 0, algorithm: 0, digest: vec![] }];
     let cancel = AtomicBool::new(false);
-    assert!(!cleanup_obsolete(&game, &old, &new, &cancel, &|_| {}));
+    assert!(!cleanup_obsolete(&game, &old, &new, &cancel, &ReplaceGate::new(), &Recorder::default(), &|_| {}).unwrap());
     assert!(!game.join("old.bin").exists());
     assert_eq!(fs::read(game.join("modified.bin")).unwrap(), b"user edit");
     assert_eq!(fs::read(game.join("untracked.bin")).unwrap(), b"untracked");
@@ -365,11 +365,48 @@ fn obsolete_cleanup_cancellation_preserves_the_old_inventory() {
     let old = vec![GameFile { path: "old.bin".into(), size: 3, algorithm: 0, digest: Sha256::digest(b"old").to_vec() }];
     let new = vec![GameFile { path: "current.bin".into(), size: 0, algorithm: 0, digest: vec![] }];
     let cancel = AtomicBool::new(true);
-    assert!(cleanup_obsolete(&game, &old, &new, &cancel, &|_| {}));
+    assert!(cleanup_obsolete(&game, &old, &new, &cancel, &ReplaceGate::new(), &Recorder::default(), &|_| {}).unwrap());
     assert_eq!(fs::read(game.join("old.bin")).unwrap(), b"old");
     let _ = fs::remove_dir_all(&game);
 }
 
+#[test]
+fn refused_obsolete_cleanup_preserves_file_and_installed_manifest() {
+    let fx = fixture();
+    let game = temp_game("obsolete-refused");
+    fs::create_dir_all(&game).unwrap();
+    for (path, bytes) in &fx.expected {
+        let path = game.join(path.replace('\\', "/"));
+        fs::create_dir_all(path.parent().unwrap()).unwrap();
+        fs::write(path, bytes).unwrap();
+    }
+    let metadata = game.join(".droiddeck-maintenance/amazon");
+    fs::create_dir_all(&metadata).unwrap();
+    let old_digest = Sha256::digest(b"old").to_vec();
+    let old_manifest = frame(
+        &message(&[vec![Entry { path: "obsolete.bin", size: 3, algorithm: Some(0), digest: &old_digest }]]),
+        b"\x08\x01\x12\x00",
+        true,
+    );
+    fs::write(game.join("obsolete.bin"), b"old").unwrap();
+    fs::write(metadata.join("installed.manifest"), &old_manifest).unwrap();
+    let target_manifest = fx.server.files.lock().unwrap()["/v/abc/manifest.proto"].clone();
+    let target_path = metadata.join("target.manifest");
+    fs::write(&target_path, target_manifest).unwrap();
+    let mut req = request(&game);
+    req.target_manifest_path = Some(target_path);
+    req.target_version_id = Some("pinned".into());
+    let cancel = AtomicBool::new(false);
+    let ev = Recorder { refuse: true, ..Default::default() };
+    let result = run_download(&req, &download(&fx), &cancel, &ev);
+    assert_eq!(result.unwrap_err(), Stop::Failed(REPLACE_REFUSED.into()));
+    assert_eq!(ev.gate_calls.load(Ordering::SeqCst), 1);
+    assert_eq!(fs::read(game.join("obsolete.bin")).unwrap(), b"old");
+    assert_eq!(fs::read(metadata.join("installed.manifest")).unwrap(), old_manifest);
+    assert!(!game.join(COMPLETE_MARKER).exists());
+    let _ = fs::remove_dir_all(&game);
+}
+
 #[test]
 fn unsupported_hash_does_not_trust_size_or_replace_existing_content() {
     let fx = unsupported_hash_fixture();
diff --git a/app/src/main/rust/stores/src/epic/install/cache.rs b/app/src/main/rust/stores/src/epic/install/cache.rs
index 4ca950d38..1c890010a 100644
--- a/app/src/main/rust/stores/src/epic/install/cache.rs
+++ b/app/src/main/rust/stores/src/epic/install/cache.rs
@@ -134,6 +134,7 @@ pub fn prepare(
 struct Rebuilt {
     bytes: Vec<u8>,
     covered: Vec<bool>,
+    uncovered: usize,
     valid: bool,
 }
 
@@ -147,6 +148,25 @@ pub fn seed_from_verified_installed(
     budget: u64,
     cancel: &AtomicBool,
 ) -> (Vec<u32>, u64) {
+    seed_from_verified_installed_with_check(
+        dir, game_dir, installed, target, needed, cached, budget, cancel, super::delta::check,
+    )
+}
+
+fn seed_from_verified_installed_with_check<F>(
+    dir: &Path,
+    game_dir: &Path,
+    installed: &Manifest,
+    target: &Manifest,
+    needed: &HashSet<u32>,
+    cached: &[u32],
+    budget: u64,
+    cancel: &AtomicBool,
+    mut check: F,
+) -> (Vec<u32>, u64)
+where
+    F: FnMut(&Path, u64, Option<[u8; 20]>, &AtomicBool) -> super::delta::Check,
+{
     const MAX_WINDOW: u32 = 64 * 1024 * 1024;
     const MAX_REBUILD_MEMORY: u64 = 32 * 1024 * 1024;
     let cached: HashSet<u32> = cached.iter().copied().collect();
@@ -157,10 +177,46 @@ pub fn seed_from_verified_installed(
         if cancel.load(Ordering::Relaxed) {
             break;
         }
+        if !rebuilt.is_empty()
+            && rebuilt.values().all(|chunk| !chunk.valid || chunk.uncovered == 0)
+        {
+            break;
+        }
         let Some(expected) = file.sha1 else { continue };
         if !super::safe_relative(&file.path) {
             continue;
         }
+        let useful = file.parts.iter().any(|part| {
+            if part.size == 0 {
+                return false;
+            }
+            let Some(&target_index) = target.chunk_index.get(&part.guid) else {
+                return false;
+            };
+            let target_index = target_index as u32;
+            if !needed.contains(&target_index) || cached.contains(&target_index) {
+                return false;
+            }
+            let Some(info) = target.chunks.get(target_index as usize) else {
+                return false;
+            };
+            if !info.window_exact
+                || info.window > MAX_WINDOW
+                || part.offset.saturating_add(part.size) > info.window
+            {
+                return false;
+            }
+            if let Some(chunk) = rebuilt.get(&target_index) {
+                let start = part.offset as usize;
+                let end = start + part.size as usize;
+                chunk.valid && chunk.covered[start..end].iter().any(|present| !present)
+            } else {
+                reserved.saturating_add(info.window as u64) <= budget
+            }
+        });
+        if !useful {
+            continue;
+        }
         let path = game_dir.join(&file.path);
         let mut safe = game_dir.to_path_buf();
         let mut no_links = true;
@@ -183,7 +239,7 @@ pub fn seed_from_verified_installed(
         if !meta.is_file() || meta.file_type().is_symlink() {
             continue;
         }
-        match super::delta::check(&path, file.size, Some(expected), cancel) {
+        match check(&path, file.size, Some(expected), cancel) {
             super::delta::Check::Cancelled => break,
             super::delta::Check::UpToDate => {}
             super::delta::Check::Pending { .. } => continue,
@@ -223,6 +279,7 @@ pub fn seed_from_verified_installed(
                     Rebuilt {
                         bytes: vec![0; info.window as usize],
                         covered: vec![false; info.window as usize],
+                        uncovered: info.window as usize,
                         valid: true,
                     },
                 );
@@ -250,6 +307,9 @@ pub fn seed_from_verified_installed(
                     chunk.valid = false;
                     break;
                 }
+                if !chunk.covered[at] {
+                    chunk.uncovered -= 1;
+                }
                 chunk.bytes[at] = byte;
                 chunk.covered[at] = true;
             }
@@ -263,7 +323,7 @@ pub fn seed_from_verified_installed(
         if cancel.load(Ordering::Relaxed) {
             break;
         }
-        if !chunk.valid || chunk.covered.iter().any(|present| !present) {
+        if !chunk.valid || chunk.uncovered != 0 {
             continue;
         }
         if target.chunks[index as usize]
@@ -389,4 +449,77 @@ mod tests {
         assert!(!cache.join(guid_text(&info.guid)).exists());
         let _ = fs::remove_dir_all(&root);
     }
+
+    #[test]
+    fn skips_verified_installed_files_that_cannot_seed_needed_chunks() {
+        let root = std::env::temp_dir().join(format!("dd-epic-cache-filter-{}", std::process::id()));
+        let game = root.join("game");
+        let cache = root.join("cache");
+        let _ = fs::remove_dir_all(&root);
+        fs::create_dir_all(&game).unwrap();
+        let needed_chunk = chunk(51, 4);
+        let unrelated_chunk = chunk(52, 4);
+        let installed_bytes = build(&TestManifest {
+            version: 21,
+            build: "installed".into(),
+            exe: "Game.exe".into(),
+            prereq: None,
+            chunks: vec![needed_chunk.clone(), unrelated_chunk.clone()],
+            files: vec![
+                TestFile {
+                    path: "source.bin".into(),
+                    sha1: Sha1::digest(b"abcd").into(),
+                    tags: Vec::new(),
+                    parts: vec![PartRef { guid: needed_chunk.guid, offset: 0, size: 4 }],
+                },
+                TestFile {
+                    path: "irrelevant.bin".into(),
+                    sha1: Sha1::digest(b"wxyz").into(),
+                    tags: Vec::new(),
+                    parts: vec![PartRef { guid: unrelated_chunk.guid, offset: 0, size: 4 }],
+                },
+            ],
+            compress: false,
+            meta_tail: Vec::new(),
+        });
+        let target_bytes = build(&TestManifest {
+            version: 21,
+            build: "target".into(),
+            exe: "Game.exe".into(),
+            prereq: None,
+            chunks: vec![needed_chunk.clone()],
+            files: vec![TestFile {
+                path: "source.bin".into(),
+                sha1: Sha1::digest(b"abcd").into(),
+                tags: Vec::new(),
+                parts: vec![PartRef { guid: needed_chunk.guid, offset: 0, size: 4 }],
+            }],
+            compress: false,
+            meta_tail: Vec::new(),
+        });
+        let installed = crate::epic::manifest::parse(&installed_bytes).unwrap();
+        let target = crate::epic::manifest::parse(&target_bytes).unwrap();
+        fs::write(game.join("source.bin"), b"abcd").unwrap();
+        fs::write(game.join("irrelevant.bin"), b"wxyz").unwrap();
+        let checked = std::cell::RefCell::new(Vec::new());
+        let cancel = AtomicBool::new(false);
+        let (seeded, written) = seed_from_verified_installed_with_check(
+            &cache,
+            &game,
+            &installed,
+            &target,
+            &HashSet::from([0]),
+            &[],
+            4,
+            &cancel,
+            |path, size, sha1, cancel| {
+                checked.borrow_mut().push(path.file_name().unwrap().to_owned());
+                super::super::delta::check(path, size, sha1, cancel)
+            },
+        );
+        assert_eq!(seeded, vec![0]);
+        assert_eq!(written, 4);
+        assert_eq!(*checked.borrow(), vec![std::ffi::OsString::from("source.bin")]);
+        let _ = fs::remove_dir_all(&root);
+    }
 }
diff --git a/app/src/main/rust/stores/src/epic/install/mod.rs b/app/src/main/rust/stores/src/epic/install/mod.rs
index 56633d488..86a05cd76 100644
--- a/app/src/main/rust/stores/src/epic/install/mod.rs
+++ b/app/src/main/rust/stores/src/epic/install/mod.rs
@@ -246,8 +246,9 @@ fn cleanup_obsolete(
     new: &[FileEntry],
     new_tags: &[String],
     cancel: &AtomicBool,
+    ev: &dyn Events,
     log: &dyn Fn(&str),
-) -> bool {
+) -> Result<bool, Stop> {
     let old_selected = locale::select(old, Some(old_tags));
     let new_selected = locale::select(new, Some(new_tags));
     let key = |path: &str| -> Option<String> {
@@ -267,23 +268,23 @@ fn cleanup_obsolete(
     };
     let Some(old_keys) = inventory(old, &old_selected) else {
         log("obsolete Epic files preserved: old inventory contains unsafe or case-colliding paths");
-        return cancel.load(Ordering::Relaxed);
+        return Ok(cancel.load(Ordering::Relaxed));
     };
     let Some(new_keys) = inventory(new, &new_selected) else {
         log("obsolete Epic files preserved: target inventory contains unsafe or case-colliding paths");
-        return cancel.load(Ordering::Relaxed);
+        return Ok(cancel.load(Ordering::Relaxed));
     };
     let _ = old_keys;
     let Ok(root) = game_dir.canonicalize() else {
         log("obsolete Epic files preserved: install folder could not be resolved");
-        return cancel.load(Ordering::Relaxed);
+        return Ok(cancel.load(Ordering::Relaxed));
     };
     let mut removed = 0usize;
     let mut preserved = 0usize;
     for i in old_selected {
         if cancel.load(Ordering::Relaxed) {
             log("obsolete Epic cleanup cancelled; remaining files were preserved");
-            return true;
+            return Ok(true);
         }
         let file = &old[i];
         let Some(k) = key(&file.path) else { preserved += 1; continue };
@@ -308,10 +309,17 @@ fn cleanup_obsolete(
             preserved += 1;
             continue;
         }
+        if !ev.before_replace() {
+            return Err(Stop::Failed("The install record could not be switched to updating; nothing was replaced".into()));
+        }
+        if cancel.load(Ordering::Relaxed) {
+            log("obsolete Epic cleanup cancelled; remaining files were preserved");
+            return Ok(true);
+        }
         if fs::remove_file(&canonical).is_ok() { removed += 1; } else { preserved += 1; }
     }
     log(&format!("obsolete Epic cleanup removed={removed} preserved={preserved}"));
-    cancel.load(Ordering::Relaxed)
+    Ok(cancel.load(Ordering::Relaxed))
 }
 
 fn resume_from(stage: &Path, parts: &[PlanPart], size: u64) -> Option<HashSet<u64>> {
@@ -430,8 +438,9 @@ pub fn run(req: &Request, cancel: &AtomicBool, ev: &dyn Events) -> Result<Finish
                 &manifest.files,
                 &req.tags,
                 cancel,
+                ev,
                 &log,
-            )
+            )?
         } else {
             ev.log("obsolete Epic files preserved: no retained prior manifest is available");
             cancel.load(Ordering::Relaxed)
@@ -635,8 +644,9 @@ cache_budget_mib={} overlap_mib={} free_game={free_game} workers={} process_work
             &manifest.files,
             &req.tags,
             cancel,
+            ev,
             &log,
-        )
+        )?
     } else {
         ev.log("obsolete Epic files preserved: no retained prior manifest is available");
         cancel.load(Ordering::Relaxed)
diff --git a/app/src/main/rust/stores/src/epic/install/tests.rs b/app/src/main/rust/stores/src/epic/install/tests.rs
index 1f7987e95..a4bc57e37 100644
--- a/app/src/main/rust/stores/src/epic/install/tests.rs
+++ b/app/src/main/rust/stores/src/epic/install/tests.rs
@@ -334,7 +334,7 @@ fn obsolete_cleanup_removes_only_unchanged_prior_manifest_files() {
     ];
     let new = vec![FileEntry { path: "current.bin".into(), sha1: None, tags: vec![], parts: vec![], size: 0 }];
     let cancel = AtomicBool::new(false);
-    assert!(!cleanup_obsolete(&game, &old, &[], &new, &[], &cancel, &|_| {}));
+    assert!(!cleanup_obsolete(&game, &old, &[], &new, &[], &cancel, &Recorder::default(), &|_| {}).unwrap());
     assert!(!game.join("old.bin").exists());
     assert_eq!(fs::read(game.join("modified.bin")).unwrap(), b"user edit");
     assert_eq!(fs::read(game.join("untracked.bin")).unwrap(), b"untracked");
@@ -349,11 +349,52 @@ fn obsolete_cleanup_cancellation_preserves_the_old_inventory() {
     let old = vec![FileEntry { path: "old.bin".into(), sha1: Some(Sha1::digest(b"old").into()), tags: vec![], parts: vec![], size: 3 }];
     let new = vec![FileEntry { path: "current.bin".into(), sha1: None, tags: vec![], parts: vec![], size: 0 }];
     let cancel = AtomicBool::new(true);
-    assert!(cleanup_obsolete(&game, &old, &[], &new, &[], &cancel, &|_| {}));
+    assert!(cleanup_obsolete(&game, &old, &[], &new, &[], &cancel, &Recorder::default(), &|_| {}).unwrap());
     assert_eq!(fs::read(game.join("old.bin")).unwrap(), b"old");
     let _ = fs::remove_dir_all(&game);
 }
 
+#[test]
+fn refused_obsolete_cleanup_preserves_file_and_installed_manifest() {
+    let fx = fixture();
+    let game = temp_game("obsolete-refused");
+    fs::create_dir_all(&game).unwrap();
+    let metadata = game.join(".droiddeck-maintenance/epic");
+    fs::create_dir_all(&metadata).unwrap();
+    let old_bytes = b"old";
+    let old_chunk = chunk(90, old_bytes.len() as u32);
+    let old_manifest = build(&TestManifest {
+        version: 21,
+        build: "old".into(),
+        exe: "Old.exe".into(),
+        prereq: None,
+        chunks: vec![old_chunk.clone()],
+        files: vec![TestFile {
+            path: "obsolete.bin".into(),
+            sha1: Sha1::digest(old_bytes).into(),
+            tags: Vec::new(),
+            parts: vec![PartRef { guid: old_chunk.guid, offset: 0, size: old_bytes.len() as u32 }],
+        }],
+        compress: true,
+        meta_tail: Vec::new(),
+    });
+    fs::write(game.join("obsolete.bin"), old_bytes).unwrap();
+    fs::write(metadata.join("installed.manifest"), &old_manifest).unwrap();
+    let target_manifest = br#"{"ManifestFileVersion":"20","ChunkHashList":{},"FileManifestList":[]}"#;
+    let target_path = metadata.join("target.manifest");
+    fs::write(&target_path, target_manifest).unwrap();
+    let mut req = request(&fx, &game);
+    req.target_manifest_path = Some(target_path);
+    let cancel = AtomicBool::new(false);
+    let ev = Recorder { refuse: true, ..Default::default() };
+    let result = run(&req, &cancel, &ev);
+    assert_eq!(result.unwrap_err(), Stop::Failed("The install record could not be switched to updating; nothing was replaced".into()));
+    assert_eq!(ev.replaced.load(Ordering::SeqCst), 1);
+    assert_eq!(fs::read(game.join("obsolete.bin")).unwrap(), old_bytes);
+    assert_eq!(fs::read(metadata.join("installed.manifest")).unwrap(), old_manifest);
+    let _ = fs::remove_dir_all(&game);
+}
+
 #[test]
 fn a_cancelled_run_reports_cancel() {
     let fx = fixture();