What does question mark in Veeam Explorer for SQL mean?

Challenge

In Veeam Explorer for SQL some of the databases listed have a question mark.

Cause

Question mark indicates lack of metadata for a database which may cause restore to be not fully functioning. Moreover restore points for such databases are not shown in the Enterprise Manager.
Most probable reasons are:
-    Due to lack of permissions metadata was not properly collected. Point-in-time restore will not be available.
-    Database was excluded from application-aware image processing. Such a database is in crash-consistent state.
-    Application-aware image processing was disabled for the whole virtual machine. Databases are in crash consistent state.
-    Database files are located on the disks excluded in job settings. Restore for such a database will not work.

Solution

If fully functioning restore is essential, resolve the underlying issue. Note that new run of image-level backup is required, although restore from existing backup still will be partly unavailable.