I ran into problems too. Start the installer from an administrative command prompt. Do not simply double click the installer If you run into any issues, just uninstall and do a fresh install. The least error prone way to install is using the local administrator user.
Is the App Volumes Manager service running?
Are you using custom certificates and used a .cer instead of a crt? in that case an upgrade will go succesfull but .cer are not taken with the upgrade backups. So you are missing the certificate.
I had the same issue today after an attemot to upgarde from 2.14 to 2.17. After some investigation it turned out to be an incompatibility with SQL Server Express 2008.
I originally installed AV 2.13 which came with SQL server express 2008, I upgraded after that to AV 2.14.3 without any problem. Today I wanted to upgrade to 2.17 but ran into a problem after the upgrade seemed to have worked well (no problems noted during the install). The AV web page displayed "Unable to start App Volumes Manager - ODBC::Error: 42000 (102) ...." (see attached screenshot).
After investigation it appears that SQL server express 2008 is not anymore supported as from AV 2.16.
- Stop AV manager service
- take a backup of the database (just in case)
- De-install AV 2.14 (leaving the DB intact)
- upgrade SQL server Express 2008 to SQL server Express 2014 (whcih comes wit the AV 2.17 install)
- Install AV 2.17