Currently in our company we have version 10.2.3 of CA Spectrum, and we will be ready to update to version 10.3.2, where we find problems with the length of the username that exceeds the maximum exceeded of 16 characters.
As additional information it was recently created to proceed with the change of user and password of the local user. Due to company policies there should be no local users on the servers and we resort to making the change to a domain user with administration permissions on the server.
Release : 10.3
Component : Spectrum Core / SpectroSERVER
The reason you are getting such error (Username exceeded maximum allowed length of 16 characters) is because of the currently design of the Archive Manager with MySQL server.
When the Spectrum was designed, the MySQL version was 5.3 and it had the maximum allowed length of 16 characters for usernames.
In MySQL 5.7.8 the maximum length of MySQL user names was increased from 16 to 32 characters, but the Archive Manager limitation kept.
Set back the Spectrum Install Owner account to a Windows Local Account and proceed with the upgrade and then change back to Domain Account. Of course the Archive Manager/MySQL will be still using the original account as it is just an account to connect to MySQL server.
We fixed this issue in DX Spectrum 10.4.1 release.
https://community.broadcom.com/communities/community-home/digestviewer/viewthread?MID=797553
https://techdocs.broadcom.com/content/broadcom/techdocs/us/en/ca-enterprise-software/it-operations-management/spectrum/10-4-1/release-information/issues-resolved.html
Installer throws a 'Username exceeded the maximum allowed length of 16 characters' error.