Check your Activity log – you may be surprised to learn that SpiderOak stopped sycning a long time ago. This has happened to me several times now. If you’ve reached the point where you’ve googled variations of “SpiderOak stopped syncing” and landed here I’m going to assume you’ve already stopped and started the application, rescanned, and rebooted.
The next thing to check is the version number of your software. If you’re not on the latest one it may stop syncing. This happened to me once I believe because they updated security certificates. There’s no way around that – you have to update.
If you’ve tried all the basics and you’re running the newest version the only thing left to do is reinstall SpiderOak. It’s not as bad as it sounds.
In OSX delete it from your Applications directory, and check to see if there’s a SpiderOak directory in /Library/Application Support. If so, delete it. Don’t touch your Hive or other synced folders! Go to https://SpiderOak.com/download/ to get the latest version and reinstall. When you sign back in look for an option labeled “Reinstalling an existing device”. It may be a bit buried. Select that. All set.
If it still doesn’t work I’ve got nothin’ for you. Sorry.