1) 'The document “*.numbers” could not be opened. ' and 2) '"untitled" can't be opened right now. Numbers couldn't read the file'

In general the solution that works most of the time seems to be:

Make sure you are running the latest version of Numbers on ALL of your devices.

Make sure you are running the latest iOS/iPadOS.

Once this is the case, shut down your Mac and restart in "safe" mode, open some Numbers documents, close them, shut down your Mac, and restart normally.

SG

I haven't been able to save a Numbers spreadsheet for over a week, after upgrading to Catalina. The fix recommended did work. Thank you. Hopefully, the Catalina gremlins won't reappear. AppleCare had told me that Apple engineers were working on a solution, but didn't have any remedy when I contacted them 3 days ago.

Looks like a necessary evil to Force Quit it...

filecoordinationd(8) BSD System Manager's Manual filecoordinationd(8)

NAME

filecoordinationd -- system-wide file access coordination

SYNOPSIS

filecoordinationd

DESCRIPTION

filecoordinationd is used by the Foundation framework's NSFileCoordinator class to coordinate access to files by multiple processes, and to

message registered NSFilePresenters.

There are no configuration options to filecoordinationd. Users should not run filecoordinationd manually.

But...

Since this is all undocumented, I can only give our current understanding: There’s ubd, the process that actually talks to Apple’s cloud servers, gets update notifications, splits and transfers files, etc. librariand is the process that maintains the list of currently available files, the sync states, ongoing transfers and exposes all of this to Spotlight. And, last but not least, filecoordinationd. This is the file locking mechanism that makes sure only one app is writing on a file at a time. It’s also the system part of the previously discussed file notification system.

Now, as soon as there are deep hierarchies, lots of files and lots of changes, things start to fail. We have seen scenarios with each of the three subsystems broken, sometimes even beyond system reboots and iCloud deactivation/reactivation. Add a few hundred packages, open some of them, run background processes and start moving stuff around -- you can be sure that file coordination will break. In our experience it will just randomly stop reporting file changes. I may also happen that file accesses are never granted. Folder deletions have to be tried, aborted and retried in some cases.

https://www.macobserver.com/tmo/article ... -is-broken

I'm not sure this is the same problem, but...

I installed a new user and moved all my files over. Since then, when I try to save files, it often tells me I can't and I need to do a "save as". Then I go and delete the original and rename the file properly.

This doesn't happen with all my files, but it does happen to the same files repeatedly.

There are four pages of responses so work through from the beginning to find the solution by SG and how to delete a curious process called Filecoordinationd. I'm afraid I don't understand it so can't explain it but it worked for me so hopefully it will for you.

Here's the Link...

https://discussions.apple.com/thread/250815175?answerId=251668268022#251668268022

It worked...I restarted the computer and the Numbers spreadsheet file saved normally, without an error message -- go figure!

Yes, curious isn't it? The old adage of switch-off/switch-on seems to be proved true.

I don't store much in the Cloud but I can report that I have had no further problems since that reboot.

Thanks. Yes I have those updates from 3 days ago.

Wow... Thank you!

Actually, killing the process 'filecoordinationd' is way quicker than rebooting the system.

Should be fixed by apple though... 😡

YOU've fixed it !!! filecoordinationd quit did it. I can open pages, numbers files, .png screenshots. Let's hope it lasts more than a day, which is about all the reboot did. Thank you so much !

Thank you. That worked. But this shouldn't be happening so I assume it's a bug in the latest OS?

Thanks for the thought but, Yes, always up to date on all devices.

Oops gave the wrong "latest MacOS". (I'm still on Mohave). iOS/iPadOS version is correct, though.

SG