Recently encountered this issue after attempting to install Veeam B&R v9 on a server that at one stage in its life had an instance of Veeam B&R installed then uninstalled.
I cannot comment on how it was uninstalled but my first installation of Veeam B&R went smoothly, I utilised the existing Veeam DB and ran a couple of backup jobs. Unfortunately, after a couple of days, several issues started to happen. Essentially the existing DB was no good and I needed to wipe the slate clean.
After several unsuccessful installations later, Veeam was now having a problem when creating the database during installation.
The exact error was ‘Failed to create database VeeamBackup.Create failed for database VeeamBackup’
What finally fixed the problem was to uninstall the Veeam B&R Server perform the following steps to clean up SQL.
Step 1. Open the directory C:\Program Files\Microsoft SQL Server\MSSQL11.VEEAMSQL2012\MSSQL\DATA
Step 2. Find the below files and delete them
Step 3. Reinstall Veeam B&R
If the above fails to work try uninstalling all SQL components and then manually delete the left-over Microsoft SQL folder in the program files. Once completed, reinstall the Veeam B&R Server.