access denied: help!

For no reason I can fathom, I'm starting to get the following prompt when opening libraries in the last 24 hours.

app.box.com/s/bpjbm5kf56kwsphc4vbz0y0myi6ao4a1

My outfit:
OS: El Capital 10.11.2
Mac: Mac Pro Late 2013, 3 Ghz 9-Core Intel Xeon E5, 32 GB, and FIREPRO D700
FCPX: 10.2.2
Media: saving media outside the library but within common folder on a Pegasus R6.

I'm juggling about four end-of-year projects all on the same system. Some open without issue; others, such as the one I need to work on now; don't.

Tried connecting the Pegasus to a Retina Macbook Pro. The library in question opens fine, but I have a bucketload of relinking to do and I'd rather not switch.

I've tried deleting preferences. That's not helping.

Any suggestions? I'm in a bit of a time crunch.

Thanks,

Tom

A follow up to my own query above: if I reboot the MacPro, I'm back in business. Very strange, and inconvenient when you have a bunch of other applications and files open.

Anyone have any experience with this behavior?

(The system, not me.)

Tom

I get the same issue occasionally except our setup is pretty different. We run 3 MacPros off a SmallTree NAS. All our libraries are kept on the NAS and occasionally that error pops up when trying to open a library. I fix the problem by copying the library to the desktop, deleting the server copy and copying it back. No idea why this happens. I'm guessing it's something to do with permissions.

launch activity monitor.app, check, if you managed somehow to launch two instances of FCPX ... :blink:

shouldn't be possible, but had that once or twice with other apps .....