I was recently working on a DPM 2010 Install and needed to force tapes that had data on them that was within a retention policy period to be free as I needed to do an urgent backup onto these LTO 5 Tapes.
DPM doesn't allow you to mark tapes as infinitely over writable, even if you put in 0 days or weeks it will always default back to 1.
So here is a cool powershell script from Microsoft. So visit HERE paste the script into notepad and save as ForceFree.ps1 and copy it into the DPM Bin Folder. And run this command ForceFree.ps1 -DPMServerName
The tape libary I was using was a "Hewlett Packard 1/8 G2 Autoloader (x64based)" So I entered this info into the command switch when running the force.ps1 powershell script but kept getting an error message saying " Cannot find tape libary Hewlett Packard 1/8 Autoloader (x64based).
So the fix for this is really simple ,
So as per image above on the right hand side , click on Rename Libary. In my case I renamed the libary to LTO5 and then re-ran my powershell script with the new tape libary and it worked fine and I was able to use the tapes to backup data.
Also don't forget to enable quick erase via regedit for tapes.