Office 365 PowerShell – watch out for the Object Graph error


Whilst in the Office 365 admin console the other day we noticed that many of our new user accounts that are being readied for the new term were missing their Office 365 licenses. We run a script every night to automatically license our users so something wasn’t right… let the investigation begin…

Everything *looks* OK?

Initially I thought maybe the scheduled task on the server wasn’t firing so I logged on and verified the script had completed successfully the night before, at least it appeared that way as the last result code was 0x0 (success).

I double-checked the script to ensure the logic was still sound in light of changing our MIS database and subsequent student rollover for the new academic year… nothing out the ordinary there as the script just checks for users starting with a student ID code where no licenses are applied.

Run the script step-by-step

My next plan of attack was then to run the script manually in a PowerShell window line-by-line to see what was going on. The first parts were OK, authenticating into the Office 365 service with no issues then I ran the initial filter command:

Get-MsolUser -All | Where-Object {$_.isLicensed -eq $false}

But instead of returning a list of users the command bombed out with this error:

The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter The InnerException message was 'Maximum number of items that can be serialized or deserialized in an object graph is '65536'. Change the object graph or increase the MaxItemsInObjectGraph quota. '. Please see InnerException for more details.

Looking around it seems the error is fairly common, I’m not sure whether it was triggered either by the number of users in our tenancy going past a certain level (and thus exceeding the query limit) or maybe a software update.

Either way the solution is explained clearly by the posters on a thread on

Basically the process goes as follows for an x64 server:

  • navigate to C:\Windows\Microsoft.NET\Framework64
  • go into the correct version folder based on the version of PowerShell you’re using
  • edit the machine.config file with the lines summarised in the link above
  • save and close config file

One step that isn’t mentioned was in my case the change didn’t seem to take effect until I rebooted the server

Running the unlicensed user query again after the rebooted returned the expected (large) list of unlicensed users, which I then followed up with a full run of the script to sort out all the student accounts. After that the list of unlicensed users was back at normal levels (shared mailboxes, archives etc.)


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