Failed Asset Registration
Decal and Trim Sheet Libraries can fail to register for 4 reasons
Note
If you report your issue properly, I will be able to tell you exactly what libraries are failing and for what reason.
Blender's System Console will also tell you that.
Incompatible
Incompatible libraries do not match the version DECALmachine expects.
For instance DECALmachine 2.5 when run in Blender 3.0 expects libraries to be of version 2.5, whereas DECALmachine 2.5 run in Blender 2.93 still expects version 2.1.
If incompatible librarias can be updated, the batch update tool will be shown as well.
Attention
Decals updated in Blender 3.0, whill show as incompatible in Blender 2.93, but can't be updated(or rather downgraded)!
Ambiguous
Ambiguous libraries contain multiple version indicators. This should never happen and requires individual investigation.
Corrupted
All folders in a Decal or Trimsheet library are expected to be Decal Or Trim Decal folders.
If there are any other folders in a library, DECALmachine will consider it corrupted and will not register it or attempt to update it.
Invalid
Invalid libraries are folders in the assets location without any version indicatior.
Legacy Line Smoothing
Use Legacy Line Smoothing in the VIEW3D section
With the switch in version 2.5 to utilizing the gpu module instead of the bgl module (due to its planed removal), any lines drawn by DECALmachine in the 3D view will be jagged.
To avoid this, you can enable Legacy Line Smoothing in the addon preferences. This will continue to work for as long as the bgl module is still supplied with Blender.