Anki Not Syncing | Fix Login, Conflicts, And Media

Sync is the bridge between devices. When it breaks, it can look like reviews vanished or new cards never arrived. Before you change anything, take a breath and protect your data. Your collection usually still exists on at least one device, and Anki gives you tools to keep it that way.

This guide follows a safe order. You’ll start with checks that don’t change your collection, then move to steps that can overwrite data only after you’ve made a backup. Read each step, do it once, then move on. Random tapping creates conflicts.

How Sync Works And Why It Can Fail

Anki stores your collection locally on each device. Sync uploads changes to AnkiWeb, then downloads changes to other devices. Two streams move during sync: the collection (notes, cards, scheduling) and media (images, audio). The collection is small and fast. Media can be large and slow.

When people say anki not syncing, the underlying issue usually fits one bucket. Knowing the bucket keeps you from guessing.

• Account mismatch — One device is signed into a different AnkiWeb account, so the collections never meet.
• Full-sync decision — Anki detects changes it can’t merge and asks you to upload or download.
• Network block — A firewall, proxy, captive portal, or filtered Wi-Fi breaks the secure connection.
• Time and session issues — A wrong system clock or unstable connection causes logins to expire.
• Media backlog — The collection sync completes, yet media keeps retrying and never catches up.

Your goal is to identify the bucket first. Then the fix usually takes a few clean steps, not a full reinstall.

Anki Not Syncing On Desktop: Fix Checklist

Desktop Anki is the best place to get control because it can export, create backups, and show clearer errors. Work through this list in order. Stop as soon as sync succeeds.

1. Confirm the AnkiWeb email — Open Preferences, check the sync login, and make sure it matches the same account on every device.
2. Run one clean sync — Restart Anki, press Sync once, and let it finish without switching profiles mid-run.
3. Check automatic date and time — Turn on automatic time in your operating system, restart, then sync again.
4. Test a different network — Use a phone hotspot to rule out office or school Wi-Fi filtering.
5. Turn off VPN and filtering tools — Disable them for a quick test, sync, then add allow rules if needed.
6. Update Anki — Install the current stable release, then sync again after a restart.

Desktop Anki can also appear to sync while nothing changes on your other devices. That usually means you synced the wrong profile, or you signed into the right account but you are working in a different local profile than you expect. Profiles are separate collections, and each profile has its own sync state. Check the profile name at the top of the profile switcher, then confirm the same profile is active on the device you expect to mirror.

If you recently imported a deck, merged two collections, or restored a backup, run one sync and let it finish before you open other devices. When two devices upload competing histories, you are more likely to trigger a full-sync prompt. Slow down for one clean cycle and you save time later.

If sync works on a hotspot but fails on your usual network, the network is the blocker. Captive portals can also cause silent failures, so open a browser, load any site, accept the portal page, then retry sync.

What To Do When You Get An Error Code

Errors tend to repeat. The wording matters because it points to the bucket.

• Log in failed — Re-enter your password, then check that your email matches your AnkiWeb account exactly.
• Connection timed out — Switch networks, disable VPN, and retry on a clean Wi-Fi or hotspot.
• SSL or certificate errors — Fix device time, avoid Wi-Fi that inspects traffic, and retry on a different network.
• Full sync required — Pause and make a backup before you choose upload or download.

On desktop, an error that repeats is worth capturing. Copy the full text or take a screenshot, then retry after one controlled change, like switching to a hotspot or fixing device time. That style of testing keeps you from bouncing between ten settings at once. It also helps you spot patterns, like errors that show up only on one network or only after sleep.

• Sync one device at a time — Let one sync complete before you open Anki on another device.
• Sync before big changes — Run a sync before importing a deck, bulk editing, or restoring a backup.
• Keep versions aligned — Update desktop and mobile within the same week so the sync format stays consistent.
• Leave sync running — During large media transfers, keep the app open until it finishes once.

Anki Sync Not Working On Phone Or Tablet

Mobile sync issues often come down to interruptions. The app starts syncing, the screen locks, a battery saver pauses network work, and the transfer stops half way. Fix the interruption first, then sync once while keeping the device awake.

Phone And Tablet Checks That Take Two Minutes

1. Stay in the app during the first test — Keep the sync screen open until it completes once.
2. Sign out and sign in again — Re-enter your AnkiWeb credentials to clear a stale session.
3. Disable battery saving for the app — Allow background activity during the sync test.
4. Free storage space — Leave room for downloads and media writes, then retry.
5. Switch between Wi-Fi and mobile data — A clean network path can reveal a Wi-Fi filter.

iPhone And iPad Settings That Commonly Interrupt Sync

• Background App Refresh — Enable it for your Anki app and allow Wi-Fi or Wi-Fi plus cellular.
• Low Power Mode — Turn it off during large media transfers so the app can keep working.
• Cellular limits — If you restrict cellular data for the app, sync may stall when Wi-Fi drops.

Android Settings That Can Block Sync

• Battery restriction exemptions — Set the app to Unrestricted and allow background activity during testing.
• Data saver — Allow background data so sync can finish even when the screen is off.
• Permission prompts — Approve storage or media permissions if the app asks during a download.

If mobile still fails while desktop syncs fine, reinstalling the mobile app can help. Do it only after you have a recent desktop backup and a successful desktop sync to AnkiWeb, so you can restore cleanly.

Fix Full Sync Conflicts Without Losing Progress

A full-sync prompt is the moment where people lose data. Anki shows it when it cannot merge changes across devices. You will see two choices, one that uploads your current collection to AnkiWeb, and one that downloads the AnkiWeb copy to your device.

Pick the direction based on where your newest work lives. If you studied on your phone all day and desktop is behind, you want the phone copy to win. If desktop has the newest edits and mobile is stale, you want desktop to win. When you are unsure, back up first and check which device shows the newest cards, edits, or review history.

Safe Full Sync Steps

1. Create a backup on desktop — Export your collection package, then confirm the file saved.
2. Sync the device with the newest data — Choose the option that makes that device the source for AnkiWeb.
3. Sync every other device — On each other device, choose the option that pulls from AnkiWeb.
4. Check one deck end to end — Verify new notes, scheduling, and tags match across devices.

If you accidentally chose the wrong direction, stop syncing on other devices. Restore your desktop backup, then run a full sync again with the correct source device.

Fix Media, Add-ons, And Large Deck Sync Issues

Some sync failures are not about your cards at all. Media can be huge, add-ons can break network calls, and large decks can hit timeouts on weaker connections. This section helps you isolate those patterns without turning your day into a guessing game.

Quick Symptom Table

What You See	Likely Cause	What To Try
Collection sync completes, images missing	Media backlog or media sync disabled	Run Check Media, then sync on a strong network
Sync stalls at the same percent	Unstable network or large media file	Hotspot test, then remove oversized media
Sync fails only on desktop	Add-on interference	Start with add-ons disabled, then re-enable slowly

Large audio files can slow media sync for hours. If a card has a long recording, trim it and re-export as a smaller file. Keep filenames simple. After cleanup, run Check Media again, then sync once on desktop and once on mobile on a stable connection.

Media Fixes That Keep Your Collection Safe

1. Run Check Media — Use Tools, then Check Media to find unused or missing files.
2. Remove unused media — Delete unused files so the upload queue shrinks.
3. Sync on stable internet — Large transfers need a clean path, so avoid weak Wi-Fi.
4. Let one device finish first — Allow a full media sync on one device, then sync others.

Add-on Isolation On Desktop

1. Close Anki — Fully quit the app.
2. Start with add-ons disabled — Use safe mode for your platform.
3. Sync once — Run a single sync and note the result.
4. Enable add-ons in small batches — Sync after each batch until the failure returns.

If safe mode syncs and normal mode does not, update the failing add-on or remove it. Keep add-ons updated after each Anki upgrade to avoid silent breakage.

When Sync Still Fails After These Steps

If you have tried clean networks, confirmed the login, handled full-sync prompts safely, and ruled out add-ons, you are down to a short list. It is either an AnkiWeb-side issue, a network that blocks secure traffic, or a local collection file that needs recovery.

Checks That Clarify The Situation

1. Log in to AnkiWeb in a browser — Confirm your account opens and your decks appear online.
2. Try syncing from a hotspot — If hotspot works, the regular network is the culprit.
3. Try a second device — If one device syncs and another fails, the failing device needs attention.

Recovery Steps When The Collection File Seems Damaged

1. Restore from an automatic backup — On desktop, use the most recent backup that predates the error.
2. Export a full collection package — Save it somewhere safe as your rollback point.
3. Create a fresh profile — Import the package into a new profile, then sync that profile to AnkiWeb.

Once you know which bucket you are in, the fix stays simple. At that point, anki not syncing stops being a mystery and becomes a checklist item you can clear in minutes.