Operation cannot be completed due to unknown error.

[#1]

Every time I launch Illustrator, an error appears: The operation cannot complete because of an unknown error. [CANT]
This happens since i installed latest CC version.

I uninstalled, and re-installed. It didn't change anything

[#2]

Every time I launch Illustrator, an error appears: The operation cannot complete because of an unknown error. [CANT]
This happens since i installed latest CC version.

I uninstalled, and re-installed. It didn't change anything

[#3]

Please don't attach images. Embed them in your post.

Do you have any third party plugins?

[#4]

No, I do not use any 3rd party plugins.
I downloaded the creative cloud directly from its application, I did not use any plugins.
Any suggestions to fix this error?

[#5 · Accepted solution]

Did you reset the preferences when uninstalling and reinstalling?

Other than that: you could contact Cutomer Care. They can have a look inside your system. https://helpx.adobe.com/contact.html