Sometimes you get throttled...

I've been working on a way to convert most of our M365 groups into DLs/Distribution Lists. And that's not super straight forward because it's not something people have to do often. But we had a bit of a miscommunication during the migration about what the requirements were, so now I have to correct it by converting M365 groups back to DLs. I have to first export all 2500+ M365 groups from our tenant, make sure I capture the current owners, members, names, and email addresses (creating a monster CSV file with over 25,000 lines). Then I have to exclude the groups that already have data in SharePoint or are using Teams (since these functions are not available to DLs). Part of the reason for the conversion to DLs is that in the old GSuite environment, these groups had external members and also nested groups. M365 groups can do neither of these things, so I also have to capture all the external users and nested groups from the old GSuite environment so I can add them to the DLs once they have been created. 

I finally have to delete the M365 groups, create the DLs, and add the members and owners. I also have to create mailContacts for any external users (a pre-requisite before you can add them to any DLs). Then I have to do a final pass where I add the external users and nested groups(that should now be DLs). 

I opted to break down our massive group and member list (around 25,000 lines) into 10 batches, to keep it a tad more manageable. I've been running batches since around 9am. It's 4 pm and only 4 batches have finished...So I decided to run 3 PowerShell windows so I could run multiple batches at a time and finish this today......and I got hit with a throttle warning by Microsoft...

So hopefully I didn't make things slower by running more than 1 at a time. I'll be babying this the rest of the afternoon just to make sure it doesn't error out or crash on me...