Q: this file server will not allow any additional users to log on

lol... agreed. Painful and stupid.

All I know is that upgrading to server solved the issue for me. It seems to be an issue with the number of connections that didn't exist prior to upgrading to mountain lion.

I refuse to upgrade to server to fix a bug—especially since the server app is largely just a fancy configuration front-end. So, I decided to take a closer look at /Library/Preferences/com.apple.AppleFileServer.plist.

There is one very interesting property: idleDisconnectOnOff. By default, this is set to NO. I've set it to YES since the recurring theme on this thread is that disconnects don't seem to be reducing that count toward 10 maximum connections.

I "too many users" hasn't reappeared since... but maybe it is coincidence. Anyone else want to give this a shot?

Also, I've uploaded by current com.apple.AppleFileServer.plist from a non-server Mac OS. Could someone with server upload theirs as well... I'm curious is some of these other settings get modified as part of the install.

I decided to try changing idleDisconnectOnOff to YES (on the Mac I connect to) and so far it seems to have solved the problem for me as well. That makes sense—it seems like the problem was that old connections were hanging around, not being used, but still counting toward the limit. Since those connections are idle, disconnecting should free up the slots so they're not counted toward the maximum.

Clearly there's a bug somewhere, as this shouldn't be necessary, but hopefully this will be a good workaround until its fixed. So far I haven't noticed any unwanted side effects.

sorry, but how do you change the dleDisconnectOnOff to YES ?

Regards

Open Terminal, paste this (all on one line), and press return:

sudo defaults write /Library/Preferences/com.apple.AppleFileServer idleDisconnectOnOff -bool YES

You'll be asked to enter your password. If you want to change it back:

sudo defaults write /Library/Preferences/com.apple.AppleFileServer idleDisconnectOnOff -bool NO

I'll report back what I find... Anyone else try this? I understand that it may take a while to properly test this out...

we'll see!

Been recently having the issue myself.  Trying the idleDisconnect patch as well. 

I sure hope this works. I have a couple of Macs that backup to a third Mac w/Drobo and ATV media and since ML I keep having to reset the file sharing on the third Mac due to this error. After a few days, Time Machine will no longer work and when I try to connect I get the "not allow any more users" error. There is only 2 users in the house!!!!!

Apple - Please fix this

So far so good.  It was happening constantly on my Wife's iMac but has yet to resurface since changing the Idledisconnect.  Did have to reboot the "server" MacPro after making the change probably to free up the connections.

I have been having the same issue.  Backup disk not available when backing up my MBAir to an external disk on my MacPro.  I was first getting the backup disk was unavailable and then got the connection (10 users) error a few days later.

I had thought I may have fixed the issue by using my Full Name instead of my shortname but it must have been a coincedence because the problem came back.  After using the above sudo command and restarting the backup started again.  Will monitor and check back if the problem comes back.

Thanks for the help.

I've had this issue since upgrading our household computers to ML with most computers experiencing intermitent failed Time Machine back-ups to a Drobo, connected to a MacMini that we use as a media server. Took your suggestion and changed the idle setting via Terminal this morning and voila. So far so good with two computers having successful TM back-ups for the first time in days. Thank you for your helpful advice.

Over two weeks and haven't seen issue again.  The idledisconnect appears to be working.

Nice. I'm glad this fix is working for everyone.

As I mentioned in my post, I'd love it if someone with OS X Server could post their plist. I doubt Apple swaps out AFS with OS X, so it might have something to do with the way it configures file sharing.

Thanks for the tip.

Open Terminal, paste this (all on one line), and press return:

sudo defaults write /Library/Preferences/com.apple.AppleFileServer idleDisconnectOnOff -bool YES

It worked for me when deleting the preference file did not.