I had the same error (“Error writing to process file pid.nbf”) on a windows server when I moved the data directory to another disk.
I eventually found the solution. The problem was caused by a wrong reference to the Notes data directory in the notes.ini. I misspelled “D:\Lotus\Notes\Data” as “D\Lotus\Notes\Data”. Leaving out the colon caused the error in my case. When I added the missing colon the server started correctly again.
You can delete the file completely…no need to restore it as it will get created automatically when the Domino server next starts.
Here’s more information on the file from the Notes Knowledge Base…
The PID.NBF file is the Process ID table of all Notes/Domino processes. For the lifetime of a Notes client/server, each process start or shutdown causes the process ID (PID) to be added to or removed from the PID.NBF.
In a Win32 environment, NSD uses the pid.nbf to determine, in case of a crash, if the failing process is a Notes/Domino process. The PID.NBF file is also used by Domino in a partitioned server environment. The file allows the processes associated with each partitioned server to be identified.
The PID.NBF is located in the Domino\Data directory. The PID.NBF file can be renamed or deleted. The file is recreated the next time the Domino server is restarted. If the PID.NBF file is deleted while the Domino server is running, NSD will be unable to determine the Notes processes to attach to until the server is restarted (when the new PID.NBF is created).
Do you have anything else running which possibly accesses the Domino files? For example is the nlnotes.exe program located in the Domino programs folder open when the Domino server starts up?
Is there anything in the Domino server’s Notes.ini file which loads plugins via the ‘NSF_HOOKS’ or ‘EXTMGR_ADDINS’ configuration settings?
Subject: Just found this in the Domino Knowledge Base…
ProblemYou attempt to start a Lotus® Domino® server, but receive the following errors:
"Error writing to process file pid.nbf, (other applications may be inappropriately accessing this file)
and
“File does not exist”
Solution
In one instance, the issue was related to the mapping of the Domino data directory, which was stored on a SAN. The issue was resolved by using UNC mapping in the notes.ini to reference the data directory (\machine name\data), instead of drive mapping.
Subject: RE: Just found this in the Domino Knowledge Base…
Check the user permissions on the application and data folder as well. We have had instances where we built workstations, installed software, cloned them, and later joined them to a domain. The permissions need to be set to allow the user to modify as well as read those directories, or at least that file.