There is a hidden registry setting in Windows 10, which when enabled shows the explorer.exe Process ID (PID) in File Explorer title bar, and tells if a folder window is running under the shell process, or as a separate process.
Show Process ID in File Explorer
Start Regedit.exe and go to:
Create a DWORD 32-bit value named ShowPidInTitle
Set the data for ShowPidInTitle to 1
Exit the Registry Editor. Logoff and login back or do a clean restart of the Explorer shell.
Shell process vs separate process
If the folder windows are run under the default Explorer shell, the PID of Explorer shell is displayed – indicated as “shell process: [PID]”
If you’ve enabled Launch folder windows in a separate process option in Folder Options settings, launching folders would create additional explorer.exe instance(s) with a different PID, of course. This also happens if you run explorer.exe [folderpath] directly from Run dialog. In Task Manager the additional instances of explorer.exe appear as shown below, with “/factory” parameter.
In those cases, the title bar would contain the words “separate process: [PID]”.
Not sure how this feature (in Windows 10 Anniversary Update v1607) would help end-users, but thought I’d write about it anyway.
About the author
Ramesh Srinivasan founded Winhelponline.com back in 2005. He is passionate about Microsoft technologies and he has been a Microsoft Most Valuable Professional (MVP) for 10 consecutive years from 2003 to 2012.