Fix Excel UserForm ComboBox Error

I’m working in Excel 365 and have a workbook with a fairly large UserForm that relies on several VBA macros. Everything runs smoothly until a user presses navigation keys inside any of the ComboBoxes —including the arrow keys or Page Up / Page Down. At that point Excel throws the dreaded “Automation error: The object invoked has disconnected from its clients.” An “Out of memory” message sometimes follows.

What I need from you is a clear, permanent fix. I’m looking for someone who can:

• trace the exact cause of the automation fault within my existing VBA code and form controls
• correct the faulty logic or API calls so the ComboBoxes accept all key-strokes without crashing
• ensure the solution works consistently across multiple sessions on Excel 365

I will supply the workbook and all related modules. Your deliverable is the repaired file plus a brief note (or inline comments) explaining what was changed so I can maintain it in the future. If external references or add-ins are required, just let me know in advance.

Tools you’ll likely touch: VBA, VBE debugger, possibly Windows API hooks if they’re being used.

Once the form no longer triggers the automation or memory errors under every tested key-stroke, the project is complete.