BE2010 R3 vers.13.0 64bit + DLO 7.5 upgrade/install
Target server: Windows 2008 R2 standard 64 bit + BE2010 R3 vers.13.0 rev. 5204 64bit SP2 with lates batches, had DLO option of BE2010 installed (but never used).
After installing DLO 7.5 on same server, database maintenance of BE2010 stopped working with error "Maintenance has failed: 10, Dump database failed.
I first tried to change "Log On As" account to system account with SQL services of datase, this did not help. Then I tried to regrant permissions for local and domain admins in sql database of BE2010. These did not solve the case.
I was able to fix this by uninstalling DLO option from BE2010 (which will require access to installation media) using "Tools=>Install options and license keys...".
I had installed DLO 7.5 using own separate sql instance (not the one used by BE). Installation somehow disabled DLO of BE2010 but left its database defined in sql instance of BE2010. Removing the option removed the unused database too.
I hope this will help anybody who is struggling with same issue.