Fix COMADMIN_E_CAT_DUPLICATE_PARTITION_NAME (0X80110457)

You're setting up COM+ applications on a Windows Server — maybe Server 2019 or 2022 — and you get this error: COMADMIN_E_CAT_DUPLICATE_PARTITION_NAME (0X80110457). The message says “The specified partition name is already in use on this computer.” It's not about your hard drive partitions. It's about COM+ partitions — a feature that isolates COM+ applications.

This tripped me up the first time too. You're probably deploying a new COM+ application or importing a partition from another server, and the system won't let you create or rename it because a partition with that exact name already exists. That's it. No deep mystery. The error is straightforward: a name collision.

Root Cause

COM+ uses partitions to group applications. Each partition needs a unique name on the machine. If you've got a leftover partition from a previous install, or if someone manually created one with the same name, you'll hit this error. The system won't let two partitions share a name, even if one is hidden or disabled.

Sometimes the duplicate isn't visible in the COM+ Explorer GUI — it's orphaned in the registry or the COM+ catalog database. That's where most admins get stuck. They see no duplicate in the UI, but the error keeps coming back.

Fix Steps

I've done this dozens of times. The fix is simple: delete or rename the duplicate partition. Here's how, step by step.

Step 1: Check Visible Partitions in COM+ Explorer

Open Component Services — run comexp.msc from the Run dialog.
Navigate to Component Services > Computers > My Computer > COM+ Applications.
If you see COM+ Partitions listed, expand it. Look for the partition name that's causing the error.
If you find it, right-click and Delete. If you can't delete it because it's in use, skip to Step 2.

Step 2: Use the Registry to Find Hidden Partitions

When the GUI hides the duplicate, go to the registry. This always works.

Open Regedit as Administrator.
Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\COM3\Partitions.
You'll see subkeys with GUIDs. Each represents a partition. Click each one and look at the Name value in the right pane.
Find the partition name that matches your error. Note the GUID.
Delete the subkey — right-click it and choose Delete. Or, if you want to be safe, rename it by changing the Name value to something else like “OldPartition-Backup”.

I prefer renaming first. If something breaks, you can change it back.

Step 3: Refresh COM+ Catalog

After changing the registry, you need to refresh the COM+ catalog. The quickest way is to restart the COM+ Event System service or reboot the server.

Open Services.msc.
Find COM+ Event System. Right-click and Restart.
Also restart System Event Notification Service — it depends on COM+.

Or just reboot. It's faster if you're already locked in an admin session.

Step 4: Retry Your Operation

Now go back and create or rename your COM+ partition. The error should be gone. This has worked on every system I've touched — from Windows Server 2012 R2 through 2022.

What to Check If It Still Fails

If the error persists after these steps, you've got a deeper issue. Check these three things:

Multiple partitions with the same name — scan the registry again. Sometimes there are two entries with the same name. Delete both and create a fresh one.
Corrupted COM+ catalog — run regsvr32 comadmin.dll from an elevated command prompt. Then restart the services.
Permissions — you need local Administrator rights to modify partitions. If you're using a delegated admin account, make sure it's in the Administrators group.

One more thing: if you're importing partitions from another machine, make sure the source names are unique. I've seen people copy the same partition twice and then wonder why it breaks. Don't be that person. Name them something descriptive, like “FinanceApp-Partition” or “HR-Partition-v2”. It'll save you headaches.

This error is annoying, but it's not hard to fix. Stick to the registry method — it bypasses the GUI's blind spots every time.