How to move large calenders from one Microsoft Outlook account to another advice from ChatGPT
In addition to advice below it is worth reading Microsoft’s own instructions at:
ADVICE FROM CHATGPT:
Outlook’s .CSV export via File → Open & Export → Import/Export is limited to around 2,800–3,000 items due to Excel’s row limitations and general performance caps in that method.
Here are better options that avoid that limit and can help you move the entire calendar, even with many thousands of events:
✅ Option 1: Use PST Export (No Event Limit)
If you’re using Outlook desktop (not web), you can bypass the limit by exporting to a .PST file, which does not have the 2,800 event limit.
📌 Steps:
- Go to File → Open & Export → Import/Export.
- Choose Export to a file → Outlook Data File (.pst).
- Select the Calendar from the original account.
- Choose a location to save the
.pst. - Now, go to the second account in Outlook.
- File → Open & Export → Open Outlook Data File.
- The calendar will now appear in the side panel.
- Switch to List View (View → Change View → List).
- Select all events (Ctrl+A) and drag them into the target calendar.
✅ This bypasses the 2800 item limit, works entirely inside Outlook, and gives you full control.
✅ Option 2: Use Outlook Web (for Microsoft 365 or Exchange)
If both calendars are Microsoft 365/Exchange:
- Go to Outlook Web App (OWA).
- Open both calendars.
- Use select-all in list view, then copy to target calendar.
You can only do this if both calendars are in the same tenant (e.g., work and work), not across different email providers.
⚙️ Option 3: PowerShell Script (Advanced / IT Admin use)
If you’re in an Exchange or 365 environment, you can use a PowerShell script with Search-Mailbox or Graph API to migrate calendar items. Let me know if you’d like this method – it’s best for admin-level bulk moves.
Want the Easiest Path?
I’d recommend the .PST method — it’s simple, works locally, avoids export limits, and allows easy drag-and-drop of all historical data.