Something has that one database locked in backup mode - I doubt that it is Snap Creator because it would cause everything to be locked, not just one database.
You could try running the unquiesce action, but I cannot recall for sure if this options works in SC 3.4 P2 - I know it works with the upcoming 3.5.
If it works with 3.4P2 the unquiesce option will force all databases to end backup mode. Restarting either Domino or the OS should do the same thing.
If it is just the one database and it is repeatable and you are using 3.4 P2 then the simplest solution might be to edit the config file.
In the APP section of the config file there is a parameter called APP_IGNORE_ERROR
Set this to Y (default is N). Please note that this needs to be changed directly in the .conf file - this is not currently a parameter that can be changed through the GUI.
APP_IGNORE_ERROR=Y will tell the Domino plug-in to ignore any databases that have errors - this is typically used to deal with database corruption issues, but it should resolve this as well. The one database will not be placed into backup mode, but the others will and the snapshot should continue.
At the least this will let you know for sure if it is the one database or multiple. The log file will list all the databases that are having issues.
This is expected behavior when encountering a locally protected database - the APIs are not authorized to access the database, thus generating the error message. This is a function of the IBM provided Domino APIs.
I'm not sure I understand what you mean in regards to the "Attempt to backup a database that is currently being backed up" error message.
Are you saying that the database with this error message randomly changes with each snapshot?
I am just looking to clarify.
Due to being on vacation I don't have access to a sample .conf file, so the parameter names below may not be exact...
In the agent section of the .conf file is a parameter named "AGENT_WATCHDOG_ENABLE" or similar name.
What is this set to? With SC 3.4 P2 I would recommend setting this to N.
I would also make sure that the AGENT_TIMEOUT is set fairly high - default is 300 seconds, but we usually recommend 900 seconds.
Generally I would say things are working properly from SnapCreator's perspective.
Hopefully the suggestions above will help as well.
There will be a technical report on Snap Creator and the Domino plug-in published in mid-January.
It is going through the publishing process now and the hope is to have it released around the same time as Snap Creator 3.5.
I expect to post about it here on the communities site once it is available.