diff --git a/src/main/browser/browser-profile-reset.test.ts b/src/main/browser/browser-profile-reset.test.ts
new file mode 100644
index 00000000000..df6db06e717
--- /dev/null
+++ b/src/main/browser/browser-profile-reset.test.ts
@@ -0,0 +1,158 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import type { Mocked } from 'vitest'
+import type { Session } from 'electron'
+
+const getAllWebContentsMock = vi.fn()
+vi.mock('electron', () => ({
+  webContents: { getAllWebContents: () => getAllWebContentsMock() }
+}))
+
+import { findPartitionWebContents, resetBrowserProfilePartition } from './browser-profile-reset'
+import { acquireCookieMutationLock, withCookieMutationLock } from './browser-cookie-import-clear'
+
+type SessionMock = Session & Mocked<Pick<Session, 'clearData'>>
+
+function makeSession(overrides: Partial<SessionMock> = {}): SessionMock {
+  return {
+    clearData: vi.fn<Session['clearData']>(async () => undefined),
+    ...overrides
+  } as SessionMock
+}
+
+function makeContents(session: unknown, opts: { destroyed?: boolean; onReload?: () => void } = {}) {
+  return {
+    session,
+    isDestroyed: () => opts.destroyed === true,
+    reload: vi.fn(() => opts.onReload?.())
+  }
+}
+
+describe('resetBrowserProfilePartition', () => {
+  beforeEach(() => {
+    getAllWebContentsMock.mockReset()
+    getAllWebContentsMock.mockReturnValue([])
+  })
+
+  it('clears the whole partition, not a filtered subset', async () => {
+    const targetSession = makeSession()
+    await resetBrowserProfilePartition({
+      targetSession,
+      partition: 'persist:orca-browser',
+      clearPendingCookieImport: vi.fn(),
+      clearImportedSource: vi.fn()
+    })
+    expect(targetSession.clearData).toHaveBeenCalledTimes(1)
+    expect(targetSession.clearData).toHaveBeenCalledWith()
+  })
+
+  it('forwards non-default partitions to staged-import deletion', async () => {
+    const partition = 'persist:orca-browser-session-imported'
+    const clearPendingCookieImport = vi.fn()
+    await resetBrowserProfilePartition({
+      targetSession: makeSession(),
+      partition,
+      clearPendingCookieImport,
+      clearImportedSource: vi.fn()
+    })
+    expect(clearPendingCookieImport).toHaveBeenCalledWith(partition)
+  })
+
+  it('clears the imported-source badge before the data is gone', async () => {
+    const order: string[] = []
+    const clearImportedSource = vi.fn(() => void order.push('source'))
+    const targetSession = makeSession({
+      clearData: vi.fn(async () => void order.push('clearData'))
+    })
+    await resetBrowserProfilePartition({
+      targetSession,
+      partition: 'persist:orca-browser',
+      clearPendingCookieImport: vi.fn(() => void order.push('staged')),
+      clearImportedSource
+    })
+    expect(clearImportedSource).toHaveBeenCalledTimes(1)
+    expect(order).toEqual(['source', 'staged', 'clearData'])
+  })
+
+  it('reloads every live context in the partition after clearing', async () => {
+    const order: string[] = []
+    const targetSession = makeSession({
+      clearData: vi.fn(async () => void order.push('clearData'))
+    })
+    const other = makeSession()
+    const mine = makeContents(targetSession, { onReload: () => void order.push('mine') })
+    const popup = makeContents(targetSession, { onReload: () => void order.push('popup') })
+    const offscreen = makeContents(targetSession, { onReload: () => void order.push('offscreen') })
+    const foreign = makeContents(other)
+    const dead = makeContents(targetSession, { destroyed: true })
+    getAllWebContentsMock.mockReturnValue([mine, popup, offscreen, foreign, dead])
+
+    await resetBrowserProfilePartition({
+      targetSession,
+      partition: 'persist:orca-browser',
+      clearPendingCookieImport: vi.fn(),
+      clearImportedSource: vi.fn()
+    })
+
+    expect(mine.reload).toHaveBeenCalledTimes(1)
+    expect(popup.reload).toHaveBeenCalledTimes(1)
+    expect(offscreen.reload).toHaveBeenCalledTimes(1)
+    expect(foreign.reload).not.toHaveBeenCalled()
+    expect(dead.reload).not.toHaveBeenCalled()
+    expect(order).toEqual(['clearData', 'mine', 'popup', 'offscreen'])
+  })
+
+  it('selects contexts by session identity so popups and offscreen guests are included', () => {
+    const targetSession = makeSession()
+    const other = makeSession()
+    const a = makeContents(targetSession)
+    const b = makeContents(other)
+    getAllWebContentsMock.mockReturnValue([a, b])
+    expect(findPartitionWebContents(targetSession)).toEqual([a])
+  })
+
+  it('survives a context that dies mid-reset', async () => {
+    const targetSession = makeSession()
+    const exploding = {
+      session: targetSession,
+      isDestroyed: () => false,
+      reload: vi.fn(() => {
+        throw new Error('destroyed')
+      })
+    }
+    const healthy = makeContents(targetSession)
+    getAllWebContentsMock.mockReturnValue([exploding, healthy])
+    await expect(
+      resetBrowserProfilePartition({
+        targetSession,
+        partition: 'persist:orca-browser',
+        clearPendingCookieImport: vi.fn(),
+        clearImportedSource: vi.fn()
+      })
+    ).resolves.toBeUndefined()
+    expect(healthy.reload).toHaveBeenCalledTimes(1)
+  })
+
+  it('waits for the session mutation lock and releases it after failure', async () => {
+    const targetSession = makeSession({
+      clearData: vi.fn(async () => {
+        throw new Error('clear failed')
+      })
+    })
+    const clearImportedSource = vi.fn()
+    const releaseImport = await acquireCookieMutationLock(targetSession)
+    const reset = resetBrowserProfilePartition({
+      targetSession,
+      partition: 'persist:orca-browser',
+      clearPendingCookieImport: vi.fn(),
+      clearImportedSource
+    })
+
+    await Promise.resolve()
+    expect(clearImportedSource).not.toHaveBeenCalled()
+    releaseImport()
+    await expect(reset).rejects.toThrow('clear failed')
+    await expect(withCookieMutationLock(targetSession, async () => 'released')).resolves.toBe(
+      'released'
+    )
+  })
+})
diff --git a/src/main/browser/browser-profile-reset.ts b/src/main/browser/browser-profile-reset.ts
new file mode 100644
index 00000000000..e273eb1f25f
--- /dev/null
+++ b/src/main/browser/browser-profile-reset.ts
@@ -0,0 +1,43 @@
+import { webContents } from 'electron'
+import type { Session, WebContents } from 'electron'
+
+import { withCookieMutationLock } from './browser-cookie-import-clear'
+
+export type BrowserProfileResetDependencies = {
+  targetSession: Session
+  partition: string
+  clearPendingCookieImport: (partition: string) => void
+  clearImportedSource: () => void
+}
+
+// Electron's global list includes popups and offscreen guests omitted by Orca's tab registry.
+export function findPartitionWebContents(targetSession: Session): WebContents[] {
+  return webContents
+    .getAllWebContents()
+    .filter((contents) => !contents.isDestroyed() && contents.session === targetSession)
+}
+
+function reloadPartitionContexts(targetSession: Session): void {
+  for (const contents of findPartitionWebContents(targetSession)) {
+    try {
+      contents.reload()
+    } catch {
+      // A context that dies between enumeration and reload needs no reload.
+    }
+  }
+}
+
+/** Resets one session partition while serializing against cookie import mutations. */
+export async function resetBrowserProfilePartition(
+  deps: BrowserProfileResetDependencies
+): Promise<void> {
+  const { targetSession, partition, clearPendingCookieImport, clearImportedSource } = deps
+  await withCookieMutationLock(targetSession, async () => {
+    // Clear metadata first so a partial reset never advertises an import whose data may be gone.
+    clearImportedSource()
+    clearPendingCookieImport(partition)
+    // clearStorageData bypasses trust-token, bounce-tracking, and network-history removal.
+    await targetSession.clearData()
+    reloadPartitionContexts(targetSession)
+  })
+}