How do You Lock a File in Windows to Block Deletion or Overwriting?

Technobiru :

While there are plenty of third-party programs to accomplish a task, sometimes you just want to use a built-in method to do the same thing. Today’s SuperUser Q&A post helps a reader find an awesome built-in solution to keep his files from being deleted or overwritten.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

Notepad screenshot courtesy of Dan (SuperUser).

The Question

SuperUser reader boboes wants to know if there is a built-in method in Windows 7 and newer editions to lock a file and keep it from being overwritten or deleted:

Is there a way to lock a file with in-house means so that it cannot be deleted or overwritten? I need to temporarily lock files while testing copy scripts in order to check the error handling in those scripts. Until Windows XP, I would load a file in debug.exe to lock it. Is there a way to do this in Windows 7 and newer editions?

I know that there are programs for doing this. My question is if there is a built in mechanism in Windows 7 and newer editions. Sometimes I have to check a script on a PC and do not want to install new programs for that.

There are also some good suggestions here: How to purposefully exclusively lock a file? Unfortunately, they require 3rd party tools or changing the file to a locked state.

Is there a built-in method for doing this in Windows 7 and newer editions?

The Answer

SuperUser contributors Dan and Breakthrough have the answer for us. First up, Dan:

I think PowerShell is probably the neatest way to accomplish this. Something like the following:

While paused, the above script causes the following prompt when attempting to open up “myfile.txt”:

Followed by the answer from Breakthrough:

For the curious, here is the MSDN link to the File::Open method detailing the parameters of the call (specifically, the last argument ‘None’, declines sharing the file with any other threads/processes). Likewise, provisions exist to lock the file for read/write only, or a combination thereof.

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Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

Akemi Iwaya (Asian Angel) is our very own Firefox Fangirl who enjoys working with multiple browsers and loves 'old school' role-playing games. Visit her on Twitter and Google+.