By default, if you don't change the tape or if you don't have enough space in the tape, the DPM backup process will fail in 60 minutes. In other words, DPM will not wait forever for a free tape and it will timeout within 60 minutes. You can modify the default timeout configuration by editing the registry.
Here is the procedure:
- Create a new Key called Prompting under HKLM\Software\Microsoft\Microsoft Data Protection Manager\1.0
- Under Prompting, create a DWORD Value called PromptingTimeOut
The PromptingTimeOut value is milliseconds. Also, you need to restart the MSDPM service for this to take effect.