With TDP Exchange 6.1, during a restore test, I had the following error :
ACN5909E The MAPI subsystem logon has failed. Please check that you have an active mailbox and sufficient privileges for this operation
APAR for this error : IC61079.
This error can also appears when we start the following command on the active node of Exchange 2007 cluster : tdpexcc restoremailbox alias…
In this case, the option to add on the command line is
EXCSERVER=CLUSTER_NAME (not the server name).
Adding this options helps to successfully recover the mailbox