If you’ve worked at all with the CUI and CUIx files in AutoCAD LT, you’ve noticed that it doesn’t have an “undo” button. What it does have, however, are the “Reset” and “Restore” functions.
You can find both of these tools by right-clicking on a CUI file name in the CUI editor.
“Restore” retrieves the previous version of the selected CUI file and makes it current instead. A single backup is saved automatically any time you make changes to your CUI file, just like the BAK files that are created when you save a drawing. (If you check out the folder location where your CUI files are stored, you’ll see something like acadlt.bak.cuix hanging out in there.)
“Reset” obliterates all changes you’ve ever made to the acadlt.cuix file and replaces is with the out-of-the-box CUIx file. Use this option with caution, and really as a last resort, because depending on how much you’ve changed, it can be hard to remember everything you’ll need to put back.
If you’re working with a partial CUIx file, maybe for company standard tools or your own personal shortcuts, “reset” isn’t available. (Makes sense, right, because AutoCAD LT doesn’t ship with *your* personal CUIx files.) But “restore” is still there, and can be helpful when you need to go back to a previous version.
Now, this doesn’t change the fact that it’s always a good idea to maintain your own backups. To manually save a copy of any of your CUI files, go to the Transfer tab and look for “Save as” under the drop-down.