AutoCAD forgets the folder I want the Open dialog to use.

Sometimes Autodesk will give us a variable to revert an updated command to it's legacy behavior.

One of these that's been around for a while is REMEMBERFOLDERS.  This is supposed to turn on/off the ability to use the Autodesk shortcut icons "start in" so that when you click the Open button it goes to that folder first, each time you click Open.  Currently the deault behavior is to use the last opened folder.

Here's what help says about REMEMBERFOLDERS.

REMEMBERFOLDERS

Type:	Integer
Saved in:	Registry
Initial value:	1

Controls the default path displayed in standard file selection dialog boxes.

0	Restores the behavior of AutoCAD 2000 and previous releases. When you start the program by double-clicking a shortcut icon, if a Start In path is specified in the icon properties, that path is used as the default for all standard file selection dialog boxes.
1	The default path in each standard file selection dialog box is the last path used in that dialog box. The Start In folder specified for the AutoCAD shortcut icon is not used.

 

To modify the shortuc icons "start in"

1)  Right click the shortcut icon and select Properties.

2) Modify the "Start in" field to be the folder you want.

So, if we set REMEMBERFOLDERS = 0 and then modify the shortcut icon you use to run AutoCAD and you're AutoCAD open dialog should go to that folder you specified.