Sorry, I don’t know what Synology is but I get that msg all the time. In my case it’s coming from RapidWeaver itself. If I publish and then do a save I find that RW is already doing an “auto” save due to the publishing. When this happens I get that msg above. So any time RW is saving and you save too you’ll see that. I’ve learned to wait a about 10 seconds after publishing to save (I don’t trust that RW does in fact save and there is no msg). Since then I’ve not received the msg. That’s my experience here anyway. Your’s may vary… Hope that helps.
Synology is a Network Drive, which means that a file can be accessed by multiple people. When accessed using samba, it means that CRUD privileges are usually assigned to the user and not to others e.g. client machine system user for example.
This is why I raised the question including the context of using it within a NAS. I understand this issue is not related to the NAS, which was my question after all !
RapidWeaver project files are actually a special kind of Mac folder called a package. You can actually right-click the project files and select to view the package content.
It’s the Mac OS GUI that makes these special folders(directories) look like a single file. External file systems (even the terminal on your Mac) process each individual file (could be hundreds) within the package (folder) independently, so the project file gets “out of sync” and becomes unusable.
Many other people have had issues with project files becoming corrupted and unusable when they store them on cloud services (Dropbox, OneDrive, etc) and NAS drives.
I’d suggest you keep RW project files on a local hard drive while working on it. As for backup, you can set up your NAS Drive to use TimeMachine. That gives you the an hourly backup(snapshot) for the preceding 24 hours.