Friday, 18 February 2022

Clearing down Chromebook profile data.


It's sometimes useful to be able to cleardown the Chromebook user profile data from a group or class-set of Chromebooks. This can help with odd issues you run into with respect to application caches, particularly local Android apps.

Fortunately you can do this from the admin console 

Devices -  Chrome - Devices

Select devices from the containing OU. You can only select a maximum of 50 devices at once. If you have more you simply need to repeat the process.

Click "Reset selected devices"

Select the option "Clear User Profiles".

This removes all user profile data but keeps device policy and enrolment.



Monday, 7 February 2022

Routing Google email using a subdomain

One task that Google admins have to undertake from time to time is the addition of a new DNS sub-domain to the tenancy,

This is particularly true of larger multi-academy trusts (MATS) that operate under a single central trust domain such as centraltrust.org but then allocate codes to each school site. In this case St Peters Primary School might be addressed as spp.centraltrust.org.  Larger independent school often isolate student accounts under a separate routable email domain and so require forms such as student.largesite.org.

While the process of adding new subdomains to a Google tenancy is well documented the action required to route inbound email is not always clear and admins often believe that so long as the root domain is routed correctly this automatically covers any subdomains - but this not the case. The MX records have to be added as a separate process.


What you need to do is follow the instructions for setting up MX records for a new Google domain listed - but with one major change.

Using the example of spp.centraltrust.org you follow the instructions but set spp in hostname field instead of @

Also note the instructions in the link are for switching between mail providers. You're not doing that - just adding a new subdomain. Therefore ignore all the comments to DELETE MX records.

This will create a set MX records for  spp.centraltrust.org and mail will route correctly.

In summary the procedure is 

  • Logon to your domain DNS provider.
  • Edit the root DNS zone for your school or MAT.
  • Add the corresponding Google MX records below using appropriate subdomain identifier for in the hostname field.

  • 1 ASPMX.L.GOOGLE.COM.
  • 5 ALT1.ASPMX.L.GOOGLE.COM.
  • 5 ALT2.ASPMX.L.GOOGLE.COM
  • 10 ALT3.ASPMX.L.GOOGLE.COM
  • 10 ALT4.ASPMX.L.GOOGLE.COM

Once DNS has been updated you’ll see email routed correctly.


Thursday, 13 January 2022

Google Classroom and Error - 409

 A Google Workspace user recently reported an error when adding a student to a classroom. The action failed with the error.

ERROR: 409: Requested entity already exists - 409

Checking the student list showed that the user account was not a current member of the class. Trying to remove the ‘existing’ student account also created an error.

The solution was pretty simple - the student account had been added to the class as a teacher by mistake. Quite how this occurred is being examined by the admin team. Removing the student account from the teaching team and adding it back in as a student fixed the error. 

As with most problems related to managing Google Classroom your best friend is GAM, particularly the 

gam print course <course number> 

command that provided a wealth of information and highlighted the issue straightaway.