Sometimes it can happen, that when opening a file, it seems that AutoCAD has gone crazy and the command bar says:
Enter name of drawing to open
The problem: it does not display the explorer dialog when using the command to open or save files. This is because the dialog variable is disabled.
It is solved with the command FILEDIA.
Eye!, It's not FIDELIA, like the name of the grandmother of Gijón, but FILEDIA from File Dialog.
We write FILEDIA, then Enter, we write the variable 1. And that's it.
Something similar can happen with the commands, and is solved in the same way with the variable CMDDIA.