"Working Set" folder on hosted exchange on Office 365

same issue here. folder does not exist on OWA 2013 and in outlook 2013. appears first time today. when i try deleting it i got the same error.

what's going on here?

same issue as well. The first time it showed up, it allowed me to delete it. Today it is back and will not allow me to delete it.

Same occurrence on Apple Mail 10.7 and 10.8…. and Outlook 2011 and OWA 2013 (Office365) don't show Working Set. Our exchange is on Office365.

Temp folder (from Apple or Exchange) that never got deleted properly on the Mac side?

There is some Working Set process related to Exchange Mailboxes…

Collect: Process: Working Set (MSExchangeMailboxAssistants)

http://technet.microsoft.com/en-us/library/hh361484(v=exchg.140).aspx

This is the Exchange 2010 reference, not sure where the 2013 reference it.

Thank God, I thought I was going mad. Setting up O365 for the first time today and saw this - happy to see I'm not alone.

As with you all, the folder isn't there on the web client, and can't be deleted from the Mail.app client. There doesn't seem to be a way to hide the folder either.

I have the same issue. How can I fix this error?

How very strange. The same thing just happened to me this week. I hadn't changed anything on my client side, and nothing was reported as having been changed on the server side by our IT folks. Same error.

You are not alone (using Yosemite here)! I've been using exchange for a while too and every now and then weird folders come and go that don't seem to have much purpose...it'll probably be a microsoft-side fix...and may take a while.

I'm seeing this too. Lots of odd little peculiarities with Office 365 and Mac Mail, including Mail.app crashing when adding an Exchange account. Over 4500 views of this topic!

I'm attempting to recommend Mac systems as a better direction for a medium-business client. They now use Office 365. This isn't helping!

Looks like this is a performance counter for monitoring exchange server (working set is RAM used by Exchange), and not something exposed to mail clients.

I still have no idea why this public folder exists (if that's what it is.)

I have had the same issue for some time.

I found the following thread on the Microsoft forums:

http://community.office365.com/en-us/f/158/t/251717.aspx

I do not want to use Exchange, but with both school and work I have no choice.

Well, I have an even worse experience with the mysterious "Working Set" folder. I am also running O365 on my Apple Mail client and all subfolders that I created for my Exchange account, appeared under the "Working Set" master folder. Well, it worked fine and I created a lot of sub folders and moved emails into my new folder structure.

This morning my "Working Set" folder was gone and with it, all my folders and content... Microsoft claimed it must be Apple, but they are now investigating. When trying to create a new folder for my Exchange account today, it appeared under the list "Exchange" top left corner and not under a master folder, like Working Set, as in the past.

My guess is that MS or Apple has solve the problem, but in the process deleted all "Working Set" folders with it's content

Anyone seen anything like this?

I have on all the Mac's using Mac Mail with our exchange accounts. Yesterday morning on the Working Set folders disappeared. This wasn't an issue for anybody except for one user. She like yourself had everything stored in that Working Set folder. I've been working to find it ever since. MS said it's not on their servers so it must be a local folder and hence an Apple issue.

I've resorted to running a lost file recovery utility to see if I can pull deleted data off the hard drive before it's too late.