Overview
Recurring calendar events are complex. Unlike standard emails or files, a recurring series is actually a single "rule" (e.g., "Every Monday at 9 AM") rather than a list of individual appointments.
When users modify specific instances—such as moving one meeting in a weekly series or changing its description—this creates an "Exception."
CloudM Migrate supports the migration of these patterns and exceptions between Microsoft 365 and Google Workspace. This guide outlines what is supported and the critical limitations regarding custom content.
1. Supported Scenarios
CloudM Migrate is designed to handle the following changes to recurring series:
| Scenario | Status | Notes |
|---|---|---|
| Delete an Occurrence | ✅ Supported | If you delete a specific meeting from a series, it will remain deleted in the destination. |
| Move an Occurrence | ✅ Supported | If you move a specific meeting to a different time or date, it will migrate to the new slot. |
| Change Duration | ✅ Supported | If you extend or shorten a specific meeting (e.g., 30 mins to 60 mins), the new duration is preserved. |
| Mixed Changes | ✅ Supported | A series can have deleted, moved, and duration-changed instances simultaneously. |
2. The "Metadata Limitation" (Critical)
While the time and date of modified meetings are preserved, custom content is not.
When you modify a specific instance in a series (an Exception), the destination platform links it back to the "Master Series" to display titles, descriptions, and locations.
What is Lost?
If you have customized the content of a single instance, the migration will preserve the Time, but revert the Content to match the original series.
The following per-instance customizations will NOT migrate:
❌ Custom Titles: e.g., Renaming "Weekly Sync" to "Weekly Sync - Christmas Special."
❌ Custom Descriptions: e.g., pasting meeting minutes into the body of one specific date.
❌ Custom Locations: e.g., moving one instance to a different conference room.
❌ Guest Lists: e.g., adding a specific guest to only one occurrence.
Recommendation: If a specific meeting requires a unique title, agenda, or guest list, we recommend detaching it from the series to make it a standalone single event before migrating.
3. How the Migration Works (Concept)
Understanding how the tool processes these events can help you troubleshoot if items appear to be missing.
The Master Rule First: The system first migrates the "Master Rule" (the main recurring series).
The Patching Process: Once the series is established, the system scans for your "Exceptions" (moved or modified dates).
Applying Updates: The system then "patches" the series to move the specific instances to their correct times.
Note for Google Workspace Destinations:
You may notice a slight delay (seconds to minutes) between the series appearing and the exceptions being applied. This is due to how Google generates calendar layers. Please wait for the migration to fully complete before verifying calendar data.
4. Re-migrating Calendar Data
⚠️ Important: If you need to re-migrate a calendar if events previously migrated incorrectly, you cannot simply run the migration again to update the existing events.
Instead, you will need to follow the steps below.
The Required "Clean Slate" Procedure:
Delete Events: Delete the calendar events in the destination account.
Empty the Trash (Crucial): You must permanently delete the items from the Trash/Bin. If items remain in the Trash, the API may still see them and restore them.
Clear Migration History: In CloudM Migrate, clear the migration history for the specific user(s).
Re-run Migration: Start the migration again.
Note for Google Workspace Destination:
If you follow the steps above and the user then decides to delete an exception to a recurring event, then restore it, this will result in two copies of that exception being restored to the calendar. This is due to the original exception still existing in the Google ecosystem.
5. Troubleshooting Common Issues
Issue: "I moved a meeting to Tuesday, but it still has the Monday title."
Explanation: This is expected behavior (see Section 2). The system migrates the time change, but the title reverts to the Master Series title.
Solution: Users must manually update the title of the moved instance in the destination calendar.
Issue: "I see duplicate recurring events in Google Workspace after deleting and restoring"
Explanation: This suggests the migration was re-run after deleting the destination calendar (see section 4). The user then deleted an exception to a recurring event and restored it, resulting in duplicates. This is because the original deleted exception (prior to re-running the migration) still exists in the Google ecosystem and is restored along with the user deleted one.
Solution: Advise users to remove the duplicates.
Issue: "The response status on my exceptions hasn't migrated over"
Explanation: This suggests the migration was re-run after deleting the destination calendar events. This is expected behavior.
Solution: If for some reason you do need to delete and re-migrate you should make users aware of this behavior.