diff --git a/src/main/worktree-name-retirement.ts b/src/main/worktree-name-retirement.ts
index d10a71618b7..e044110239e 100644
--- a/src/main/worktree-name-retirement.ts
+++ b/src/main/worktree-name-retirement.ts
@@ -267,7 +267,12 @@ export async function ensureRetiredWorktreeNamesBackfilled(
   )
   const scanKey = `${getRepoExecutionHostId(repo)}:${worktreePathComparisonKey(probePath)}`
   const names = await runRetirementBackfillScan(store, scanKey, () =>
-    discoverRetiredWorktreeNames({ workspaceRoots: [parentPath(probePath)] })
+    discoverRetiredWorktreeNames({
+      workspaceRoots: [parentPath(probePath)],
+      // The repo, not the workspace root, is what says which distro the agent runs in: a WSL repo
+      // whose workspaces fell back to the Windows side still buckets under the drvfs mirror there.
+      wslDistro: parseWslPath(repo.path)?.distro
+    })
   )
   // Why the merge sits outside the cached scan: the scan is per cwd namespace but the registry is
   // per repo, so every repo that asks must receive it — not only the one that triggered it.
diff --git a/src/main/worktree-retirement-discovery-wsl.test.ts b/src/main/worktree-retirement-discovery-wsl.test.ts
index 835309493d8..e1ad513fcef 100644
--- a/src/main/worktree-retirement-discovery-wsl.test.ts
+++ b/src/main/worktree-retirement-discovery-wsl.test.ts
@@ -109,6 +109,33 @@ describe('retirement discovery on WSL', () => {
     }
   })
 
+  it('traces a Windows-side workspace of a WSL repo into the distro through the drvfs mirror', async () => {
+    // `computeWorkspaceRootAsync` falls back to the drive path whenever the distro home will not
+    // resolve at create time, so a WSL repo can own workspaces under `C:\`. The agent is still
+    // spawned through `wsl.exe`, so its cwd is `/mnt/c/...` and its bucket lands in the distro.
+    const distroHome = await mkdtemp(join(tmpdir(), 'orca-drvfs-distro-'))
+    const hostHome = await mkdtemp(join(tmpdir(), 'orca-drvfs-host-'))
+    try {
+      await mkdir(
+        join(distroHome, '.claude', 'projects', `-mnt-c-users-ada-orca-workspaces-${FIRST}`),
+        { recursive: true }
+      )
+
+      const retired = await discoverRetiredWorktreeNames({
+        workspaceRoots: ['C:\\Users\\ada\\orca\\workspaces'],
+        home: hostHome,
+        env: {},
+        wslDistro: 'Ubuntu',
+        resolveWslHome: async (distro) => (distro === 'Ubuntu' ? distroHome : null)
+      })
+
+      expect(retired.names).toEqual(new Set([FIRST]))
+    } finally {
+      await rm(distroHome, { force: true, recursive: true })
+      await rm(hostHome, { force: true, recursive: true })
+    }
+  })
+
   it('stays retryable when the distro home cannot be resolved, rather than memoizing the hole', async () => {
     // `getWslHomeAsync` shells out to `wsl.exe` and returns null for a stopped or slow distro.
     // Memoizing that as a complete "nothing is retired" is the STA-4472 defect itself, since the
diff --git a/src/main/worktree-retirement-discovery.ts b/src/main/worktree-retirement-discovery.ts
index 730a8bd2630..e071795f3a6 100644
--- a/src/main/worktree-retirement-discovery.ts
+++ b/src/main/worktree-retirement-discovery.ts
@@ -93,6 +93,12 @@ type ClaudeProjectsSource = {
   encodedParents: string[]
 }
 
+/** How a distro sees a Windows drive path through the drvfs automount, which is lowercase `/mnt`. */
+function drvfsPath(windowsPath: string): string | null {
+  const drive = windowsPath.match(/^([A-Za-z]):[/\\](.*)$/)
+  return drive ? `/mnt/${drive[1].toLowerCase()}/${drive[2].replace(/\\/g, '/')}` : null
+}
+
 // Lowercased on both sides: the recorded cwd can differ in case from ours on case-insensitive
 // filesystems, and a missed bucket reissues a live path while a spurious one costs one name.
 function encodeParents(paths: readonly string[]): string[] {
@@ -116,6 +122,7 @@ async function claudeProjectsSources(args: {
   home?: string
   env?: NodeJS.ProcessEnv
   resolveWslHome?: (distro: string) => Promise<string | null>
+  wslDistro?: string
 }): Promise<{ sources: ClaudeProjectsSource[]; complete: boolean }> {
   const sources: ClaudeProjectsSource[] = []
   let complete = true
@@ -127,13 +134,22 @@ async function claudeProjectsSources(args: {
     })
   }
   const linuxRootsByDistro = new Map<string, string[]>()
+  const addLinuxRoot = (distro: string, linuxPath: string): void => {
+    linuxRootsByDistro.set(distro, [...(linuxRootsByDistro.get(distro) ?? []), linuxPath])
+  }
   for (const root of args.workspaceRoots) {
     const wsl = parseWslUncPath(root)
     if (wsl) {
-      linuxRootsByDistro.set(wsl.distro, [
-        ...(linuxRootsByDistro.get(wsl.distro) ?? []),
-        wsl.linuxPath
-      ])
+      addLinuxRoot(wsl.distro, wsl.linuxPath)
+      continue
+    }
+    // A WSL repo can still have its workspaces on the Windows side: `computeWorkspaceRootAsync`
+    // falls back to the drive path whenever the distro home will not resolve at create time. The
+    // agent is still spawned through `wsl.exe`, so its cwd is the drvfs mirror of that drive path
+    // and its bucket lands in the distro home under `-mnt-c-…`, out of reach of the host scan.
+    const mirrored = args.wslDistro ? drvfsPath(root) : null
+    if (mirrored && args.wslDistro) {
+      addLinuxRoot(args.wslDistro, mirrored)
     }
   }
   const resolveWslHome = args.resolveWslHome ?? getWslHomeAsync
@@ -163,6 +179,8 @@ export async function discoverRetiredWorktreeNames(args: {
   env?: NodeJS.ProcessEnv
   /** Injected in tests; production resolves the distro's `$HOME` as a UNC path. */
   resolveWslHome?: (distro: string) => Promise<string | null>
+  /** The repo's distro, so workspaces that live on the Windows side are still traced into it. */
+  wslDistro?: string
 }): Promise<RetirementScanResult> {
   const leafNames: string[] = []
   let refused = false