When Illustrator crashes, which happens quite often, the recovered files lose all the symbols in the cloud library. This makes the recovery system useless and all the lost work has to be redone.
This totally discourages the use of Adobe's cloud libraries.
Adobe, fix your software!
Don't. Ever. Rely. On. Recovery. Alone. Never ever.
If Illustrator crashes regularly on you, fix your system. If you can't fix it, and get help with it. Customer Care can log into your system and help https://helpx.adobe.com/contact.html
On top of that: develop a true backup strategy. Save your files early, regularly and in different versions.
The recovery function will always only be a last straw and was never meant to replace a backup strategy.
Fix my system? The computer is new and I have the latest version of Illustrator (25.0). Obviously I use a backup system because I cannot rely on the Adobe software.
Today it crashed when clicking on the remove fx button in the properties panel and lost 2 hours of work. What kind of system fix will prevent this?
All co-workers who use Illustrator have the same problems. If I don't see light at the end of the tunnel, I will start looking for alternatives for my whole company.
As for the issue with the drop shadow. I can't replicate it, but I've seen it popping up in the forums.
It seems to be linked to specific systems, system settings or hardware.
You could try if it helps when you turn off the GPU acceleration in the preferences.
Which should of course not be considered a permanent fix. Just to find out what is causing it. Did you reset the preferences when updating Illustrator? Do you use third party plugins?
As for using a backup system: no matter how reliable software is: you should always do that. Apart from software or system misbehaving, power outages, viruses etc can throw you off as well.
You got the wrong thread