Need information on the Data Loss Prevention 15.1 service_user account used during an upgrade.
Article ID: 184427
Data Loss Prevention Enforce
Essentially what happens is the upgrade keeps both versions of DLP(new and old) until the old instance is deleted. When a new service account is used, the old service account is no longer valid because it changed. This also means that the old install will no longer work.
Symantec Engineering does not take a stance on using the same user account versus a new one, however if you are planning on keeping the older install around, then you should consider keeping the account the same.
We have verified that if you keep the accounts the same and remove the old install, it does not remove the 15.1 user accounts so this should not be an issue. So my recommendation is that you keep them the same for now unless there is a reason for a new one as it sounds like there is a way to change the service account later for example, if needed for compliance reasons.
The same is true for using different accounts – nothing is effected by removing the older install except that you lose the option to run the older version if needed. We have run some tests and after uninstalling the old version the account was still present and being used by 15.1.