Hello, how can I get PS to delete/clear the LastWriteTime and LastAccessTime of files, so that only the CreationTime remains? Thanks a lot.

you can use the CreationTime property to with set_LastWriteTime and set_LastAccessTime you can reset the LastWriteTime and LastAccessTime.

gci c:\temp | % {$_.set_LastWriteTime($_.CreationTime);$_.set_LastAccessTime($_.CreationTime)}

I can't find any ways to remove completely the properties your looking for.

Thanks. That's just as good.
One problem: If I try that on folders I get an error message that the process can't access the folders as they are in use. Do you know how I can circumvent that?

gci c:\temp | ? { $_.PSIsContainer -ne $true } | % {$_.set_LastWriteTime($_.CreationTime);$_.set_LastAccessTime($_.CreationTime)}

Thanks.