So, whenever I switch from one library folder to another, I get the attached error message. I've tried changing the permissions on this specific folder but no change. It is the only folder I seem to have the problem with, and (as far as I can tell) despite the msg I can still access the contents of the folder. It's just annoying af.

Anyone?

THANKS!

File TIMES? Times? ... seriously what? I've been with Poser for over 25 years and this is a new one. It seems like the windows file system might have issues.

Try this...

Move that "Older Runtimes" folder someplace outside the "Users" folder. Windows does special permission stuff for the desktop. A security descriptor for that folder might be messed up.

Move the entire contents of the runtimes someplace like C:\Poser Files\ Then in Poser remove the old linked runtime and link to the new location.

If that works be suspicious of the hard drive. A scan with ChkDsk /f is recommended at least.

And make sure you have everything backed up.

It might be objecting to the actual user folder; typically, the content folders are placed into the 'Users>Public' folder where security is not so stringent. 

If you have a problem to access this particular file, or just a bunch of files/folders, check first that you are the owner of these file (of the runtime's whole tree would be best), to be sure: force Windows to set YOU as the owner, then reset the permission of the whole tree.
By the past, I stumbled upon a weird case: one specific file wasn't accessible, even though I could see it

I've had that message pop up only for one specific folder of Darkworld's poses.  The runtime containing those poses is on my D drive where it's always been and I had never had any issues accessing it with PP2010, PP2012, PP2014, P11, P12, P13.   Even though I got the message I could still access the folder and the poses inside.  It used to happen with P11 and P12 and even when I used Mozilla browser to open the library and then it suddenly stopped popping up.  Who knows why? 

The error you got is a discretionary access control error (it can be called an Active Directory error as well). In simple terms, it means a folder with extra security, and DACL (discretionary access control list) denied access to a read request.

It is a very common error if you keep program information in a user folder under DACL security, and something goes wrong. A few people ran into this when I was running the SM forums.

The common denominator.. Putting Runtimes in the user desktop area, and the aftermath of Poser crashing with files or directories open.... The system will find the error, repair it, and create a new default list (users that have permissions). Poof, Poser cant read it anymore because it is in a DACL directory on only the user has permission by inheritance of the root directory with a default list.... Simplified explanation, and a downside to DACL... Also a good reason why you should not put program info in those directories.

Moving the Runtime to an area that is not under DACL permissions is the best thing to do. None of that security will be there for Windows to attempt to repair..