Got Generic SQL Error issue, while uninstalling the Managed Solution.
As the Message is generic, I opened “Event Viewer”(Below is the error) in the CRM Server for the Application Logs and found that there is no enough space in the C drive (I have installed SQL in C Drive).
So, removed unnecessary files from C drive and freed up the space and tried to delete Managed solution, it was removed from the CRM Organization.
Hope this helps 🙂