Fix COMADMIN_E_LEGACYCOMPS_NOT_ALLOWED_IN_1_0_FORMAT

You're in the Component Services snap-in, right-click your COM+ application, choose Export, and select 'Application — Installable as a 1.0 format' — then boom: error 0x8011081A with the message 'Applications containing one or more legacy components cannot be exported to 1.0 format.' I know this error is infuriating, especially when you're just trying to package something for another server.

This usually hits when you've got old-school COM components — think VB6 DLLs or early COM+ code — that were registered with the LegacyComponent flag. That flag tells COM+ these components pre-date the modern COM+ infrastructure, and the 1.0 export format doesn't know how to handle them. The real fix: you need to either ditch the legacy flag or migrate those components.

Step-by-Step Fix

Before you start, you'll need admin rights on the machine. I'm assuming you're on Windows Server 2012 R2 through 2022, or Windows 10/11 Pro.

1. Open Component Services. Hit Win + R, type dcomcnfg, press Enter. Navigate to Component Services > Computers > My Computer > COM+ Applications.
2. Identify the problem app. Expand the application that's failing. If you see any components that look like old VB6 or OCX files, that's your culprit.
3. Check the legacy flag. Right-click each component under the application, choose Properties, go to the General tab. Look for a checkbox labeled 'Legacy component'. If it's checked, that's what's blocking the export.
4. Remove the legacy flag. Uncheck that box, click OK. If the component is pure COM+ — meaning it doesn't rely on old threading models or secondary apartments — this alone might let the export work. But wait: some components break if you uncheck this because they were designed for a single-threaded apartment (STA). If you see odd behavior later, you'll know why.
5. Try the export again. Right-click the app, choose Export, pick 'Application — Installable as a 1.0 format', and click Next. If it succeeds, you're done. If not, the component really needs converting.
6. Convert legacy components to standard format. This is the nuclear option, but it's the right one for apps you maintain. Open the component's source code in Visual Studio (6.0 or later), find the DLLRegisterServer or DllInstall entry point, and remove any call to CoRegisterClassObject with the CLSCTX_LOCAL_SERVER flag. Recompile the DLL. Then unregister the old version (regsvr32 /u old_component.dll) and register the new one (regsvr32 new_component.dll). Back in Component Services, refresh the app — the component should now show as a standard COM+ component without the legacy flag.
7. Final export test. Export again to 1.0 format. Should work cleanly now.

If It Still Fails

Check three things. First, make sure no other components in the app still have the legacy flag — I've seen apps with a mix of legacy and standard components, and the export fails if even one legacy component remains. Second, verify the app isn't using any unsupported features for 1.0 format: for example, partitioned applications or queues won't export to 1.0 format either. Third, look at the application's Security tab — if you've customized impersonation levels or authentication beyond 'Default', the 1.0 format might reject it. In that case, export to 'Application — Proxy' format instead, which preserves those settings. It's not ideal for installation, but it's a workaround.

This error is one of those 'Windows Server gotchas' that trips up admins who've been at this for years. Once you've cleaned out those legacy flags, you'll be exporting apps like it's 1999 — but in a good way.