WOW, I'm very confused. I just went into a folder that one of my employees was working in and there are duplicate files for every InDesign file except a .P has been added to the duplicated filenames before the .indd. Example: "Section 10 [2017 49-59 ].indd" and "Section 10 [2017 49-59 ].P.indd"
There are several folders, each with several InDesign files that have different created/modified dates, but it appears that all the .P files were generated on the same day at approximately the same time. The file sizes of the files with the .P are smaller than the original by approximately 20-25%.
Any suggestions? I'm on a Mac running Yosemite with InDesign CC 2014 and he was on a Windows 7 using InDesign CC 2014.
Sounds like one of your systems is running a script or plugin that creates the duplicate files. You might check the startup scripts folders—startup scripts launch on startup and can run in the background.
On OSX startup scripts can be in two places:
user/Library/Preferences/Adobe InDesign/Version 10.0/en_US/Scripts/startup scripts
Applications/Adobe InDesign CC 2014/Scripts/startup scripts
Otherwise look for third party plugins that might be creating files