Access reports that another .NET version is loaded

A WKL control doesn't appear, and Access shows the message “Another .NET version has already been loaded in this Access process …” with the code 0x800080A5. The VBA call that accessed the control fails with an error; Access keeps running.

The start module shows this message before .NET is running and without the application model, so its language follows the Office language in Access, then the Windows language, and otherwise English (English, German, Slovenian, Croatian, or Italian), even if the application model sets a different language for the components. In releases up to 1.56.2, the message is in German for every language, and its umlauts appear as two wrong characters (“öffnen”).

Every release of the WKL Forms Object Library, 32-bit and 64-bit Office.

A process can run only one version of .NET (CoreCLR). Another add-in or control built on a different .NET version (5 through 9, or a later one) loaded its runtime into Access before the WKL control started. The start module of the WKL controls detects this and shows the message once per Access process instead of failing silently. Add-ins built on .NET Framework 4 don't cause this problem; both runtimes run side by side.

1. Restart Access and open the database without the other add-in (switch it off under File › Options › Add-ins, or remove its control from the startup form).
2. If you need both in the same database, ask the vendor of the other add-in for a .NET 10 build, or open the forms with WKL controls before the forms that use the other add-in.
3. To identify the other runtime, reproduce the message and look for coreclr.dll and its folder among the modules loaded in MSACCESS.EXE (for example, with Process Explorer).