Cryptomator encrypts data locally. No explicit need to sync them to an online storage. But due to my opinion, there is “better” software that is designed for local encryption only, like veracrypt.
That should be possible. Please post the exact error message here. Or the log file.
Yes
No. The detection is actually only implemented for the most “common” providers. If you use other providers, you have to select the respective folder manually with “custom location”.
sorry, I do not have a recommendation, mybe other users?
Theres no benefit when using a cryptomator vault inside a verycrypt container or even worse nest a veracrypt container into a cryptomator vault. Please don’t do that. Veracrypt is a local, well checked encryption. No need from my point of view to add an extra local encryption. And it will have effects on performance
yes, if you sync your encrypted files to an encrypted online storage you have a doubled encryption. Only if you do not trust the providers encryption, this can be a useful setup (personal opinion).
(please not: encrypted or not, every attacker has to first breach your cloud storage account to have access to your cryptomator files).