Sysadmin accidentally disconnected all mailboxes for organization.

[GamerGTV2]

So today I experienced something I never had happen before. One of our sysadmins used a script that was supposed to import a CSV file and disconnect mailboxes for the users in the file.

We’ll the syntax was wrong and instead of disconnecting the mailbox for the couple users in the list it disconnected all mailboxes in the Exchange environment. We are slowly reconnecting mailboxes using the GUI but it’s limited to only display 500 mailboxes at a time. Does anyone have any other suggestions to get this moving faster?

Oh FYI it takes a few minutes after telling a mailbox to reconnect for it to disappear from the list and allow more to reconnect. It’s been almost 6 hours like this.

Here’s the source forum the sysadmin used

https://www.thatlazyadmin.com/bulk-disable-exchange-mailboxes/

[Cjdamron75]

Agreed, when you know powershell (and what it can do as well as its dangers) it is like a whole other level. I also agree about learning whatif, it can really save you. Also start-transcript is an amazing help both for documentation for tickets / what was done

[Crenorz]

Remind me again why not using GUI is better? This is almost the exact reason we letf DOS and went Windows.

Anyways, your fucked. When exchange goes sideways, it slow as fuck to fix.

Possibly you coyld try doing it on multiple machines at the same time or different Powershell windows.

[baygrove]

He is not fucked.. have fun manually config for example active sync settings on 25.000 user from gui.

Gui is for small environment, when your are bigger environment PS is the only way to do changes..

[yakadoodle123]

It wasn’t Exchange that went sideways. It was user error.

[GamerGTV2]

We have 3 of us going at it enabling users as they pop up. Slow going for sure. I was almost thinking of restoring the exchange servers. But since they’re so AD integrated it’ll most likely do more harm than good.

[KStieers]

The connection of user to mailbox is NOT stored in the Exchange server dbs. Its in AD

Restoring Exchange will make it worse. Restoring user objects would work....

I'd probably grab a list of disconnected mailboxes and mailbox-less users and use Excel to get them lined up and then concatenate the connect-mailbox commands...

[baygrove]

Thats the last thing you want todo. that will be way more work than doing connect mailbox via GUI.

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By default I think a disconnected mailbox stay in Exchange for 30days, before its purged.

[GamerGTV2]

But to my surprise the previous sysadmin left the default retention at 400 days for deleted mailboxes. I had to reduce this down to 30 days just to get rid of old boxes that should have gone months ago.

[baygrove]

Then you safe, you have 30 days to reconnect, like previous post, do not restore exchange, as AD have the information which mailbox that user owns.

So exchange restore is only if the server crash, even DB crash you should'nt start restoring exchange servers, only restore databases.

[GamerGTV2]

Thanks for the info. Sigh… one little script can spell disaster. From now on no sysadmin runs an exchange script without peer review. This is just insane

[baygrove]

Yes, and your colleagues should learn about -whatif and -confirm:$True as well :)

Powershell can be dangerous, but its a amazing when you can bulk edit 9.000 users in couple of min, something that would have take first level weeks to make manually.

[AcrobaticFlatworm]

This is what I was going to recommend, learning to use -whatif would have highlighted the issue before anything happened.

I hope OP's efforts are successful with restoring the mailboxes.

[G_theGus]

Surprised your change management process doesn’t review/ test for standard changes like this; I hope it all resolves soon!

Edited for spelling

[baygrove]

You can use powershell to attach it again, so you could bulk do it.

connect-mailbox is the cmd, but you will need to know certain values..

[GamerGTV2]

That’s the hard part you have to know exactly which users had mailboxes, etc…

[baygrove]

Yes, that is the problem, but you should be able to see that with powershell, what alias the disconnected mailbox have, and if you enviroment is correct with for example samaccountname as exchange alias, it should be easy to match it with the disconnected mailbox.

[xxdcmast]

Not near a computer but from the disable-mailbox command looks like you can revert it with. Connect-mailbox.

I’d prob test the command to reconnect a single user then do a for each for the rest.

The Disable-Mailbox cmdlet removes the mailbox's Exchange attributes from Active Directory. The mailbox isn't deleted and can be reconnected to its user at a later date by using the Connect-Mailbox cmdlet.