You want to reset AutoCAD to defaults in order to correct a problem that results in program crashes, inability to start, error messages, or other issues. autocad reset
Causes:
Most AutoCAD functions are a result of values loaded from settings files and registry keys. Resetting the program to defaults will restore the program to its original settings.

Solution:
Each user account on a system will have its own AutoCAD settings. Resetting to defaults will only affect the currently active user account. To reset in a different account, you must first log in to that user.
Windows 7 Operating System:For most versions of AutoCAD 2012 and later (including AutoCAD-based products), the reset utility can be found in the AutoCAD program group located in the Windows Start Menu:

How to reset AutoCAD to default


Start menu ==> All Programs ==> Autodesk => AutoCAD 201x => Reset Settings To Default.





The reset utility gives you the option to back-up your settings first. Once the reset is complete, AutoCAD automatically opens and initiates its secondary installer
Windows 8 Operating System:
1. Click the Windows button to access the Start Screen.
2. Right-click the bottom of the screen.
3. Click the down arrow to access all the installed apps.
4. In the AutoCAD section, click Reset Settings to Default.

Windows 8.1 Operating System:

Click the Windows button to access the Start Screen.
Move your cursor down and click the down arrow to access all the installed apps.
In the AutoCAD section, click "Reset Settings to Default."

How to reset AutoCAD to default
How to reset AutoCAD to default

AutoCAD 2011 and older on the Windows 7 and Windows XP Operating Systems:
For AutoCAD 2011 and older and versions that do not have the Reset utility, one must reinitiate the secondary installer
AutoCAD for Mac 2014 SP1 and later:
To reset the palettes:
 Click the Window menu and choose Reset Palettes or enter RESETPALETTES on the command line.

To reset the entire program:

Hold down the Shift key while starting AutoCAD for Mac. In AutoCAD for Mac 2015, you may click the AutoCAD menu and choose Reset AutoCAD. For all versions of AutoCAD for Mac, do the following:

1. Click Preferences under the AutoCAD menu.
2. Click the Application tab.
3. Click the button Reset Application Options.
4. Click Reset AutoCAD.

Windows 10 Operating System:
  1. Click the Windows button to access the Start menu.
  2. Click 'All Apps'
  3. Click the down arrow v to expand 'Autodesk'.
  4. Scroll down and click on 'Reset 201x Settings To Default'.