When this error pops up
You'll see CO_E_MISSING_DISPLAYNAME (0X80080015) when an app tries to activate a COM object — and that object's CLSID registry key has no Default value set. I've seen it most often with third-party software installers that skip a step, or after a Windows update wipes a registry entry. For example, a VPN client or a cloud sync tool that depends on a COM class will throw this on launch.
What's actually happening
Every COM class in Windows needs a human-readable display name stored under its CLSID key. The default value (empty or missing) means the system can't identify the class, so activation fails. The registry path looks like: HKEY_CLASSES_ROOT\CLSID\{some-GUID} — and the default string there must contain something, even just a short name like "MyApp Component".
Step-by-step fix
- Find the failing CLSID – Look in your app's event logs or in the error message itself. It usually includes a GUID (e.g.,
{12345678-1234-1234-1234-123456789012}). - Open Regedit – Press Win + R, type
regedit, and hit Enter. - Navigate to the key – Go to
HKEY_CLASSES_ROOT\CLSID\{your-GUID}. If the GUID isn't there, the class itself is missing — reinstall the software. - Check the Default value – Right-click the Default string in the right pane. If it's blank or (value not set), that's the culprit.
- Add a display name – Double-click Default and type any descriptive name. Use something simple like
Class {your-GUID}or the app's component name. - Restart the app – Close and reopen the program that triggered the error. No reboot needed.
What if it still fails?
Check two things:
- Is the GUID correct? Typos happen — copy-paste from the error.
- Does the CLSID have subkeys like InprocServer32 or LocalServer32? Without those, the display name alone won't help. If missing, the class registration is incomplete; reinstall the software.
Pro tip: I keep a backup of CLSID keys before editing — just export the branch. Saves a headache if something goes wrong.