Last Updated on March 11, 2021
One of my testing/sandbox computers, that’s not running on a UPS, was unexpectedly powered off the other day when a falling tree branch in my neighborhood took out a power line. Hours later when the power was back and I turned on my computer, one of my virtual machines running on VMware Workstation 12 wouldn’t start and had an error that mentioned “Failed to Lock the File” and “Module Disk Power on Failed”.
Of course, the first thing I did was a search on google that lead to quite a few promising results.
I ended up on this VMware Community forum post and after a bit of reading I found the answer. It involves some .lck files that must be deleted, which are “Lock Files” that are created while Virtual Machines are running so that the filesystem is only edited by the controlling Virtual Machine and not outside sources. When my computer’s power was cut off unexpectedly, the Lock Files weren’t automatically deleted as they are supposed to be when a VMware VM shuts down.
How I Fixed the “Failed to Lock the File” and “Module Disk Power on Failed” Errors
First thing to do is open up the directory where your virtual machine’s files are stored. I used poorly named folders for my VMs like an asshole, so I had to look at my VM’s “Virtual Machine Details” dropdown on it’s Workstation tab to see which directory it was in.
After getting into the correct directory for my Scrapebox VM, I looked for all the folders with .lck ending and made a backup of them before deleting. The backup was just in case deleting the files didn’t fix the problem and I needed them back, you can see the backup .zip highlighted in the below screenshot.
However, thankfully my backup wasn’t needed because deleting all of the .lck files fixed my “Failed to Lock the File” and “Module Disk Power on Failed” error. My virtual machine started up without any issues with the .lck files removed!

John started JSnowCreations as a place to post random tech guides and product reviews. However, while shopping for his daughter’s first “big girl” bed in 2019 he learned about the hidden dangers of fiberglass in mattresses. Since then, John has made it his mission to expose as much hidden fiberglass in mattresses as possible. His ultimate goal is federal regulations that ban fiberglass from being used in mattresses, or at least a law that require it to be listed in the material tags.