No, I didn’t know that either.
So in other words, if you want to use the Server copy of a file, instead of the copy stored on the PC, you can do that by adding $NOCSC$ to the file path.
Another way of putting it, it causes the local computer to bypass the local file cache, and to grab the file from the file server.
I only found out about $NOCSC when a customer complained that their Roaming Profile was broken. Looking at the event log I saw the strange $NOCSC$ entry
Log Name: Application
Source: Microsoft-Windows-User Profiles General
Date: 17/01/2016 17:15:09
Event ID: 1509
Task Category: None
Windows cannot copy file C:\Users\BigEars\AppData\Roaming\Microsoft\Windows\Cookies\BigEars@fred.desk.txt to location \\server01$NOCSC$\Profiles$\BigEars.V2\AppData\Roaming\Microsoft\Windows\Cookies\BigEars@fred.desk.txt. This error may be caused by network problems or insufficient security rights.
DETAIL – Access is denied.
There is no Microsoft documentation on $NOCSC$ which means that it is unsupported for customer use. The earliest reference to $NOCSC$ I can find is an event log reference in this Microsoft TechNet blog article from March 2008. The earliest suggestion to use it, for debugging purposes, is from Microsoft’s Ned Pyle in March 2009.
It would seem that the earliest operating system to support it, is Microsoft Vista.