Migration to Jira Cloud - Custom fields and screens are getting duplicated

Question

We are migrating to Jira Cloud instance with existing data that came from the same server instance that the current migration is coming from.

The server instance is a Test instance which getting refreshed once in few months with new data from production Jira Server.

I noticed that if there wasn't a Server refresh in that period of time between the 2 phases of migration, everything looks good and we don't have any duplications, but after we did a refresh to the Test server instance and then the 2nd phase migration, all the custom fields and screens are getting duplicated.

We need to know of someone encountered this before and how to avoid this.

If it's not possible to avoid this, it will be helpful to know how to fix it on Cloud post-migration and merge the duplicated fields, using scripts or any other possible solutions.

Kh_Safal · Answer

@David Day_ Appcento, this topic has been locked because the thread has become a bit dated. If you’d like to keep the conversation going or have additional questions, we encourage you to start a new topic. You can read more about necro posting (“raising threads from the dead”) in our Community Guidelines.
Thanks!

David Day: Appcento · Answer

Hey Mayur,
Just came across this thread and wanted to share what we learned the hard way going through the exact same thing.
So the short answer is: yes, this is totally expected JCMA behavior, and no, there's no way to fully avoid it during the migration itself. When JCMA sees that a field with the same name already exists in the target Cloud site, it doesn't try to be smart about merging or matching. It just creates a new copy with "(migrated)" slapped on the end. It's a safety feature to prevent data loss, but yeah, it leaves you with a mess to clean up after.

What we found works best is a two-step approach:

Before migration (prevention):
If you know you're doing multiple migration waves from the same source, try to migrate all projects that share the same custom fields in one batch. That way JCMA only creates the duplicates once. I know that's not always possible with phased migrations though.

After migration (cleanup):
This is where it gets tedious but manageable. Here's what we did:
1. First, do a full scan of your fields to identify all the "(migrated)" pairs
2. For each pair, check if the original field has data or if it's empty
3. If the original is empty, you can safely copy the migrated values over
4. If both have data, you'll need to decide which values to keep (this is the painful part)
5. Once you've merged the data, update your screens/workflows to point to the original field
6. Then you can safely delete the migrated copy

We ended up building a small script for this because doing it manually for hundreds of fields was taking forever. It scans all fields, detects the "(migrated)" pairs, and flags which ones are safe to merge vs. which ones need manual review.
One thing I wish someone had told us earlier: don't rush to delete the migrated fields right away. Archive them first, wait a week or two, and make sure nothing breaks. We learned that the hard way when a dashboard stopped working because it was referencing a field we thought was unused.
If you're interested, you can check it out here: Migration Field Cleanup for Jira

Matthew Joslin_AppFox_ · Answer

We speak to a lot of admins going through this and guaranteed - cleaning up before migration is much easier than after.
Once duplicates land in Cloud they're harder to untangle, and you'll hit the 700-field cap faster than expected. Would recommend our app Optimizer for Jira here.

It's designed for this prep phase as it surfaces unused custom fields, screens, workflows and schemes via smart tables so you can bulk delete or archive in one action, with a config merge option that consolidates duplicate fields while preserving historical data.

Works on both Data Center pre-migration and Cloud post-migration, so the same toolkit covers both sides of the move. Got some neat Rovo-assisted actionable advice integration, too. 
Free 30-day trial via the Marketplace, if it sounds like it could help you.