> For the complete documentation index, see [llms.txt](https://docs.qwertycoin.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.qwertycoin.org/nodes-and-builds/fix-sync-issues.md).

# Synchronization Troubleshooting

> **Verified against:** the latest stable Core release; exact review revisions are recorded in the [Source and version matrix](/contribution-and-evidence/source-version-matrix.md).

Diagnose before changing data:

1. Check `qwertycoind --version` and the configured network.
2. Compare local height with multiple healthy peers/explorer observations.
3. Check incoming/outgoing peer counts and the system clock.
4. Check disk, filesystem errors, memory pressure and OOM events.
5. Check firewall/NAT reachability for P2P `8196`.
6. Read logs around the first error, not only later retries.

Common causes are a legacy data directory, blocked seed/peer connectivity, insufficient disk, an uncleanly copied LMDB, wrong permissions or a clock far from network time.

Do not delete wallet files, seeds or EPoSe keystores. Do not import historical CSV checkpoints to suppress a symptom. A normal full resynchronization replaces only blockchain data. EPoSe additionally requires endpoint, identity and lifecycle checks.