Visual Studio 2013 error: Get Latest from version control

Ran into an interesting Visual Studio error today while coding in C#: when I tried getting the latest versions from TFS source control, Visual Studio 2013 gave me this error:

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Microsoft Visual Studio
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Get Version: Operation not performed 
Cannot perform the source control operation at this time because
some of the files involved in this operation are locked. Please
retry the operation at a later time. 
Please refer to the Output window for more information.
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OK   
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The Output window listed the files that were causing the trouble.

What was the remedy? Trying again didn't help, but restarting Visual Studio did. I could have been related to Windows Defender, or then no. Nonetheless, I don't recall seeing this error before, so I might be pretty rare to run across this one.

Hope this helps!