syncing issue since creation of multiple group libraries
I have a shared group library with 552 references & 4 collections; recently i copied the 4 collections and made them each an individual group library, while still keeping the original group library. Since then, I have had trouble syncing while working in zotero standalone. I increased my storage to unlimited, so storage space is not the limiting factor. Here is the error report number from the last time I tried to sync - 1073195126.
You may be able to work around it yourself by pasting QMZ46DF5 and P97YAK3B into the Zotero search bar in All Fields & Tags mode at the root of your group libraries and, in the items that come up, checking the creator names for invalid characters (or emoji, possibly) and removing them.
To be clear, I don't believe these have ever synced in Zotero — they use characters (corrupted characters, or possibly emoji or other rare four-byte Unicode characters) that will take a bit of work to support.