Symptoms
Plesk installer shows a warning:
Plesk installation doesn't support 'Debian Backports/buster-backports/main' OS repository
Cause
Backport repositories are unsupported to avoid potential stability risks.
According to the official website, backports cannot be tested as extensively as Debian stable, and backports are provided on an as-is basis, with the risk of incompatibilities with other components in Debian stable. Use with care!
Resolution
- Log in to Plesk via SSH
- Identify repository files where backports are defined:
# grep -ir Backports /etc/apt
- Comment out backport repositories in all identified files (by placing a hashtag "#" at the beginning of the string). Normally, it is
/etc/apt/sources.list