AutoCAD Inventor :: Checking In While Closing Vault?

Having problem when using Inventor to check in a (large->slow) file while closing vault at the same time?

One of my colegues had a drawing file lose some of his changes when he checked in.  we could not see a reason why, as the file was in vault with the correct time stamp.  the file was the same as the previous check in.

This morning i have had a similar problem, where by i had made changes before checking in last night and when i opened the file in the morning the changes where not there.

I looked on my c drive in old versions (before i did anything else to overwrite it!) and low and behold the changes there!

The only thing i remember doing that was not normal was to close Vault while this large file was in the process of checking in through inventor.