If you have this problem don’t worry.
1. in window directory type REGEDIT
2. Check that next key in the registry is setup = 1:
KEY_CURRENT_USER\Software\Autodesk\AutoCAD\R19.0\ACAD-B001:409\Profiles\your profile\Dialogs\Select File - PreviewVisible =1
If it’s already = 1, turn it to “0” (zero), launch AutoCAD, run the open command (the preview area should not be visible). Close AutoCAD, and change the value of the key back to “1”