We'll add this in the Lima preferences in the future.
In the meantime, you can take the following steps to change it on your own:
1. Quit Lima Application.
2. Launch registry editor, go to:
3. Replace the drive letter with an unused one. First of all, you need to know what are your available letters in order to pick the right one. To do so, please open Computer or Windows Explorer and press the Alt key. Select Tools > Folder Options, and click the View tab. Under Advanced settings, uncheck 'Hide empty drives 'in the Computer folder. Click OK.
4. Restart you computer.
In the screenshot below, the L has been changed by a N.