PowerShell script to check an application that's locking a file?

You can do this with the SysInternals tool handle.exe. Try something like this:

PS> $handleOut = handle
PS> foreach ($line in $handleOut) { 
        if ($line -match '\S+\spid:') {
            $exe = $line
        } 
        elseif ($line -match 'C:\\Windows\\Fonts\\segoeui\.ttf')  { 
            "$exe - $line"
        }
     }
MSASCui.exe pid: 5608 ACME\hillr -   568: File  (---)   C:\Windows\Fonts\segoeui.ttf
...

You should be able to use the openfiles command from either the regular command line or from PowerShell.

The openfiles built-in tool can be used for file shares or for local files. For local files, you must turn on the tool and restart the machine (again, just for first time use). I believe the command to turn this feature on is:

openfiles /local on

For example (works on Windows Vista x64):

openfiles /query | find "chrome.exe"

That successfully returns file handles associated with Chrome. You can also pass in a file name to see the process currently accessing that file.

This could help you: Use PowerShell to find out which process locks a file. It parses the System.Diagnostics.ProcessModuleCollection Modules property of each process and it looks for the file path of the locked file:

$lockedFile="C:\Windows\System32\wshtcpip.dll"
Get-Process | foreach{$processVar = $_;$_.Modules | foreach{if($_.FileName -eq $lockedFile){$processVar.Name + " PID:" + $processVar.id}}}