project or library file cannot be opened

[billko]

You should be able to mass compile the folder?  Come to think of it, I don't know if that would mass compile the project.  You might be able to manually edit the project file, though.  I've heard of people doing that to rescue their projects.

[DahlmanR]

It looks like some individuals were having this issue several years ago, and they found that the issue was with the Windows Security/Sharing permissions on the files (http://forums.ni.com/t5/LabVIEW/LabVIEW-8-5-1-project-file-cannot-be-opened-by-other-users/td-p/7366...). I would check to ensure that your user account has security permissions for the project. 

Here's an external link on changing file permissions: https://technet.microsoft.com/en-us/library/cc754344(v=ws.11).aspx

R Dahlman
National Instruments

[faustina]

I'm using Windows 10 and I have gone through the process of setting permissions for all the folders, sub-folders, and their files.  The VIs and LLB files will open but not the project file.