Data.dm Files

I keep seeing "data.dm" files in my list of checks-outs. What are these files and what should I do with them?

The data.dm files (prop.xx files in IC5.X) contain property information for the cell or library, such as CDF data.
These and other library/cell level files can be checked out and checked in automatically.
If your preferences are set to disallow auto-checkin, you can checkin the files normally using VersIC.