Are You Frustrated with Jumbled Outlook Calendar Colors After Migration? Discover the Ultimate Solution.

Why Are My Shared Calendar Colors a Disaster After Moving to Exchange Online, and How Can I Fix It Permanently?

Moving from a local Exchange server to Exchange Online is a common upgrade. This process usually goes smoothly. However, sometimes small, confusing problems appear. One such issue is when calendar colors, used for categorizing appointments, suddenly display incorrectly for others. Let’s explore why this happens and the best way to resolve it.

The Core Problem: A Mix-Up in Color Categories

Imagine you have a set of labeled folders in your office, with names in German. You then move to a new office that provides a standard set of folders with English names. When you bring your German folders over, they don’t automatically match the new system. Your “Wichtig” (Important) folder might not be placed in the red “Important” slot; it might just be put wherever there is space.

This is what happens during a specific type of Exchange migration.

Local vs. Cloud Categories

Your old, on-premises Exchange server had its own list of color categories, perhaps in a local language like German. When you export your calendar to a file (.pst) and import it into the new Exchange Online system, you are introducing a custom list into an environment that already has a default list (usually in English).

A Conflict of Lists

Exchange Online doesn’t automatically merge these two lists or match them by color. It sees your imported German category names as new, separate entries. Since the default English colors are already assigned, your imported categories get the next available colors in the list, leading to a mismatch.

Why It Looks Right for You, But Wrong for Others

Initially, your own Outlook application might cleverly remember your local settings from the import file, so the colors look correct on your screen. However, when a colleague views your shared calendar, their Outlook requests the information directly from the Exchange Online server. The server only knows about the new, mismatched color assignments, so your colleague sees the “wrong” colors.

How to Fix the Color-Category Problem

There are two main approaches to solving this issue. One is a quick fix, while the other is a more permanent solution for an organization.

The Manual Reset (The Quick Fix)

This was the solution found by the administrator in the story. It involves manually adjusting the categories in Outlook for the affected user.

1. Open the calendar and go to the “Categorize” menu.
2. Select “All Categories.”
3. Delete the unwanted default (English) categories.
4. Rename and re-assign the correct colors to your imported (German) categories.

This works but can be time-consuming. The problem might reappear, and it has to be done for every person who faces this issue.

The Administrator’s Solution (The Better Way)

For a lasting and consistent fix across a company, an IT administrator can use a tool called PowerShell. This allows them to manage Exchange Online settings directly.

• Create a Master List: An administrator can define a single, standard set of calendar categories and their assigned colors for the entire organization.
• Deploy the List: Using a script, they can push this master list to all user mailboxes. This action overwrites any personal, local, or mismatched categories.
  This method ensures every user has the exact same categories and colors, eliminating confusion when sharing calendars. It solves the problem for everyone at once and prevents it from happening again.