Hi, I have a file used by couple of people in my company. It contains a lot of vba code and few user forms. It's been working perfectly for years now on all machine. Recently 1 machine has been migrated to Windows 10, the excel major version hasn't changed though (16). For reason unknown, 1 of the forms lost almost all the controls on it and the user is getting "Compile error: Method or data member not found" at the line Me.cmbWeek.ListCount (as this control is not existent for the machine, although all other machines 'see' it perfectly well (also migrated to Windows 10 but flawless). You can find both form and its code behind here: github.com/robs23/ProductionSchedule/tree/master/Forms. Now, how can I debug what's wrong? It's nothing with the file as it has worked for years on several machines including machine of this user (until he went on Win10). Checked references and there's nothing missing either.. Please find below the forms both on user's machine (broken) and on all other users' machines (proper).