Challenges Doing SPOnline to SPOnPrem2019 Modern Migration using ShareGate Tool


Hi guys, let's try to understand a few challenges faced while doing a Modern SPOnline to SP2019 On-Prem ShareGate Migration.

I did a few migrations from Online to On-Prem 2019 both for Modern Environments. I am disappointed with a few things that the Tool has missed while migrating with this process. I shall also try to include a suitable solution to the below points. Users can give me a better alternative if they have found a smarter approach.

1. Custom Theme Missing: The custom theme is not supported by the migration tools, and hence needs to be re-developed only with the REST API combined with JS Injection using SPFx, as SPOnline PS commands can't be used on OnPrem environments. For a better idea please check this link:

2. Twitter/Yammer Feeds which were User dependent didn't show up on my On-Prem Destination Modern site: Here, your SPOnline User Account is dependent on Modern WPs content not being migrated or shown, hence you need to have same AD Users in the SP2019 On-Prem to maintain the Sync.

3. Pages migrated but are not working. One is a Home page, hence I can't make it a Home page: Here also, we need to redevelop the Modern Pages, as they are affected by the above scenario.

4. A simple Calendar SPD WF wasn't migrated: Need to check the dependencies before we start up the Migration. If there are no such dependencies and they still have not migrated, then we need to re-develop it and cover it under Post Migration Challenges.

5. Why are no Hub/Communication Site Template options missing in the Site Template section of the Mappings option: Due to this, I keep selecting a wrong template, which leads to missing structure and content. Here, it's very difficult to migrate with an exact replica of the source in the destination. A work-around has been added to the community site template option for the above scenario, but it still needs further work.

6. A Few Navigation links are connected to the other Sites/Applications which are also not migrated or available: We need to first check the Navigation links. If they are connected to any other Modern sites/Applications, we need to make sure that they are migrated first using the same approach. Always migrate the Dependencies first, they could be the Lists/Look Up columns/Site Columns/Content Types/Other Sites, etc.
Other Best Practices:
  1. Always make a User Permission Matrix report to check for any bad users/complexities.
  2. Check for the Options tab and select Merge with your site, but not to migrate a subsite to your Expected Destination Site. Similarly, make the right selections for the Operations and Configurations sections too. Similarly, give a proper value to the Dependencies tab.
  3. Now check for the Mappings. Tab map all the unresolved users and groups to your SPAdmin. Make the proper Site Templates mapping, and if not, do the approximate suitable Templates mappings at least. The last section is the Permissions.
  4. Run the Pre-Check Scan Report before proceeding to the actual migration. 
  5. Check for the Warnings/Errors mentioned in the above report and try to fix them with the solution.
  6. For example, all unknown/unrecognized/bad users can be mapped to SPAdmin for a seamless migration.
  7. Now run the Actual Migration without any wifi disconnection/breaks in your internet connectivity.
  8. Export the migration reports too, for quick analysis and to get some solutions directly with the ShareGate Team when unable to crack what has to be done at that moment for a few scenarios.
That's all. Have a Great Day :)