Thanks for your reply.
I'm not sure either.
I can, naturally, only speak for myself, but I liked the previous behavior much more. Here's why: I have some folders on SSD that contain hundreds of files. For performance reasons, those folders are not compressed (decompression uses too much CPU). But a handful of the files are very large (multiple GB), and must be compressed to prevent filling up the SSD. Thus the folder is not compressed, but specific files are compressed.
When the new version of FreeFileSync tries to back up these folders, performance is significantly degraded. The backups are written to external HDDs, and writing those files without compression is lethargic. Plus, of course, it causes backup storage to fill up where previously there was sufficient storage.
This seems to be one of those "there is no absolutely one right way" situations. So maybe an option that the user can toggle is in order?
BTW, unrelated, if you get a moment to look at this, it will be appreciated:
viewtopic.php?p=36166