Set the Window Option to Overlapped Windows, Go to File/Options/Current Database, under Document Window Options, select Overlapped Windows instead of Tabbed Documents. Adjust the form's property sheet, open the form in Design View and verify the following settings on the format tab Auto Resize: Yes, Auto Center: Yes, Fit to Screen: No, Border Style: Thin or Dialog (Avoid Sizable if you want to lock the dimensions), Min Max Buttons: None or Min Enabled (to prevent manual maximization)

Since .accde files lock the Design View and compile VBA, you can not make design changes directly on the .accde file. You must apply these fixes to your original .accdb source file and then recreate the .accde.

As an alternative approach lock dimensions & position via Form Properties and VBA. Adjust the form's property sheet, open the form in Design View and set Auto Resize: No, Auto Center: No (Set to No so it doesn't override the custom top/left coordinates), Fit to Screen: No, Border Style: Thin or Dialog (Avoid Sizable if you want to lock the dimensions), Min Max Buttons: None or Min Enabled (to prevent manual maximization) and set form dimensions and position on open or on load event like

Private Sub Form_Open(Cancel As Integer)
' DoCmd.MoveSize [Right], [Down], [Width], [Height]
' Right: Distance from the left edge of the screen (X position)
' Down : Distance from the top edge of the screen (Y position)
' Example:
' Left: 1000 Twips (~1.8 cm), Top: 1000 Twips (~1.8 cm) Width: 8000 Twips (~14 cm), Height: 5000 Twips (~9 cm)
  DoCmd.MoveSize 1000, 1000, 8000, 5000
End Sub

Alkan is right that you have to make any design changes in the original ACCDB file, then create a new ACCDE.

The ACCDE format itself shouldn't change the width of a form. What usually changes is the environment where it opens, especially whether the database is using Tabbed Documents versus Overlapping Windows, along with different screen resolutions or Access window sizes.

If this is meant to be a fixed-size pop-up style form, check these form properties in the ACCDB:

Auto Resize: No
Auto Center: Yes
Fit To Screen: No
Border Style: Dialog
Pop Up: Yes
Modal: Yes, if you don't want users clicking elsewhere until they close it

Also make sure the database is set to Overlapping Windows if you want Access to honor the form's window dimensions. In Tabbed Documents, forms are displayed as tabs, and their apparent size can behave differently.

After changing those settings, close and reopen the database so the Current Database option takes effect, test the form, and then create a fresh ACCDE.

Thank you, I will try that. I have NEVER used Tabbed Documents! You have always said not to do that!
To me, using tabbed documents would be illogical, as Mr. Spock would say.

Yeah, I'm still not a big fan of Tabbed Documents. They have improved a bit over the years, and I did recently spend some time playing with them again. They're getting better. That said, feel free to experiment with them. They may work fine for some databases, but they still have enough quirks that I wouldn't call them my first choice. Mr. Spock's logic remains sound.

I definitely avoid them for forms that are VBA-heavy or rely on lots of code. For a simple form where you just want to display different groups of information, they can be fine. For example, customer demographics on one tab and preferences on another. But for anything code-heavy or code-dependent, I would stick with Overlapping Windows and subforms.

Thank you!