CO_E_NOCOOKIES (0X8004E02A) — Cookie Write Failed

This error is a pain

You're trying to run an app or service, and bam — 0x8004E02A shows up with 'An attempt to write a cookie failed.' It's a COM+ issue, not a web browser thing. I've seen it on Windows 10, 11, and Server 2019 after bad updates or manual registry edits.

The fix — reset the COM+ catalog

Here's what works 9 times out of 10. Open an admin command prompt. Run this:

cd /d %windir%\system32\com\

comadmin.exe /e /r

This resets the COM+ catalog. It doesn't touch your user data, but it wipes all COM+ applications. You'll need to recreate any custom ones. Wait 30 seconds after the command finishes. Then restart the service or app that threw the error.

If the command fails, the COM+ catalog is locked. Reboot into Safe Mode with Networking, then run it again. In Safe Mode, COM+ services are minimal, so the reset goes through clean.

Why this works

The COM+ catalog stores configuration info in a binary file under %windir%\system32\com\. When something corrupts it — like a failed update or a bad uninstall — COM+ can't write its internal cookies. These aren't browser cookies; they're temporary tokens COM+ uses for object activation. Resetting the catalog rebuilds that file from scratch, fixing the write path.

Plan B — registry fix if reset doesn't stick

Sometimes the catalog reset works, but the error comes back after a reboot. That means a registry key is corrupted. Open regedit as admin. Go to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\COM3\

Right-click the COM3 key and export it as a backup. Then delete the entire key. Reboot. Windows recreates it cleanly. This has fixed stubborn cases where the catalog reset alone failed.

Warning: Deleting COM3 will break any custom COM+ applications you installed. You'll have to re-register them. For most people, that's zero — only system defaults use this.

Less common variations

I've seen this error in two other situations:

1. Antivirus blocking COM+

Some aggressive antivirus software blocks COM+ from writing temp files. If resetting the catalog didn't work, temporarily disable your AV. If the error goes away, add an exception for %windir%\system32\com\ and %windir%\system32\dllhost.exe. This happens most with McAfee and Norton.

2. Corrupted user profile

On rare occasions, the issue is tied to a specific user profile. Create a new local admin user, log in, and test. If the error doesn't appear, the old profile's registry hive is damaged. You can fix it with a profile rebuild — but that's a separate long process.

Prevention — keep it from coming back

Three things cause this:

1. Bad Windows updates — especially cumulative updates for Server 2019. Before installing, check the support forum for COM+ issues. If you see reports, delay the update.
2. Manual registry edits — don't touch the COM3 key unless you know what you're doing. I've seen admins tweak it for performance and break everything.
3. Third-party COM+ tools — some ancient management tools rewrite the catalog. Only use Microsoft's comadmin.exe or Component Services snap-in.

That's it. Reset the catalog, or nuke the registry key if it's stubborn. You'll be back up in 10 minutes.