KB-1278 "Cannot migrate: There is no migration path" error thrown in gw-*.log or APP window after engines fail to start

Symptoms

Engines fail to boot up. The following error will appear in the gw-*.log for Linux and in the app window for Windows:

Cannot migrate: There is no migration path

Cause

This issue can be caused by one of two things:

1. You copied engine database files (*.kdb) from a newer version of Appian to an older version of Appian. By newer version of Appian, this can include major version (16.3 vs. 16.2) or hotfix (16.2 Hotfix Package B vs 16.2 Hotfix Package A).
2. A hotfix has been recently applied, but this hotfix was applied incorrectly, so the installation now has code mixed from the new hotfix and the previous version/hotfix.

Action

If this occurred right after a migration, recopy the engine database files to the same or newer version of Appian.

If this occurred right after applying a hotfix, reapply the hotfix.

Affected Versions

This article applies to all versions of Appian.