Two common system variable errors that I get contacted for is firstly that the DEL key on the keyboard does not seem to work. Now the idea is that you select the object and then press the Del key. Usually this will obviously delete the objects but in this case is does not. Note that you select the objects first and then press the key. This “pre select” function where you can select the object before the tool is controlled with the system variable called “pickfirst” which should be set to 1 to enable.
You can also set this system variable in the Option Dialogue box under the Selection Tab. The option is on the left of the dialogue box called “Noun/Verb” selection and it should be ticked as shown:
The other system Variable controls the OPEN dialogue box and when you click the open button no dialogue box appears very similar to the screenshot of the command line below.
If this happens press ESC to exit the open command enter “filedia” system variable command on the command prompt. Set it to 1.
Once this is done if you click Open you’ll get the Open Dialogue box once more.
How these system variables change is usually in the event of a system failure. What happens is as you work you are in the middle of a command. The command is a script and it has changed the system variable at the start of the script and before the command can finish and change back the system variable to its original state AutoCAD crashes or a system failure happens leaving the system variable in its undesired state.