Symptoms
When running a migration to Microsoft 365 while using Insane mode, you get one of these error messages on one or several of your items:
This item was not copied due to a fatal error on item '{0}' at the source. Fix the error or skip the item to complete the copy.
This item was not copied due to a fatal error on an item at the source. Fix the error or skip the item to complete the copy.
This item was not copied due to a fatal error on an other item. Check for items with error in this report.
Error Code
AZ-034-213
AZ-048-368
Details
When you migrate to Microsoft 365 in Insane mode, your items are packaged and sent to Azure storage before they are imported to their SharePoint destination by Microsoft 365.
Often, Azure responds with fatal errors when a package reaches 100 errors during import. Corrupt files can also cause a fatal error from Azure.
Microsoft 365 stops importing the whole package the moment one of its items receives a fatal error during the import process, and you get an error message on all your items in that package in your migration report.
For example, if you migrate a list that breaches its 50,000 unique permissions limit, each subsequent item will get an error at the destination. In this case, your import package can rapidly reach 100 errors and give you an error on all the remaining items.
To learn more about the Azure import process, see SharePoint to SharePoint migration diagram.
If you get fatal errors, you can:
Look at your migration report for errors you can solve that might cause the fatal error.
Use Copy content only to migrate the other items and skip the items that cause the fatal error.
Migrate the affected library in Normal mode.
While we do not recommend complete migrations in Normal mode, it can help you discover the underlying errors since this mode sends your content directly to the destination.
If you are breaching the total amount of unique permissions, restore the permission inheritance of your items or uncheck Permissions in your copy options.
If you must preserve these permissions, you can split your content into multiple lists or libraries to avoid breaching the 50,000 unique permissions threshold.
Try to download, open, or move the affected files manually. You might find they are corrupted or unreadable for various reasons.
If you need further help, our Support team can assist you.