Is there a way to exclude .zip files from the 'Files without thumbnail' Files with Problems section of the Dashboard? I have a few of these in the folders monitored by IMatch. By their nature, .zip files don't have thumbnails; therefore it's misleading and distracting to see them show up in a Problems list.
As you said, ZIP files have no thumbnail, so they show up in this statistic. The same is true for text files, code files, HTML files and other formats which have natively no thumbnail.
This entry does not indicate a problem, it's just an indicator. There are no filters available for this entry.
Feel free to add a feature request if you want additional options for this.
The odd thing is that only .zip files show up in my 'Files without thumbnails' even though I have a number of .txt, .html files and others that I don't think have thumbnails.
I've added a feature request: https://www.photools.com/community/index.php?topic=12098.msg86010#msg86010