Clean Windows Registry

21 Jan 2009

The Registry Clean utility on the Field PC provides a method for recovering from situations when the Windows CE/Mobile operating system is locking up, stuck, or corrupted due to a Windows registry problem, but you also want to be able to recover files from the internal flash storage memory prior to performing a full Clean Boot (setting all memory to a factory defaults state). Instructions are provided in the steps below.

Note: If you perform a Registry Clean, it is always recommended to perform a Clean Boot (Set Factory Defaults) after recovering files, or to restore the Windows registry from a backup. This will prevent unassociated program files from remaining in memory, which could cause other issues and take up needed storage space.

Windows Mobile

  1. Perform a Reset by pressing and holding the Power (On/Off) button for 3-5 seconds, and then select Reset from the list (or continue to hold the Power Button until the screen flashes off briefly).
  2. Immediately press and simultaneously hold the following keys just until a couple seconds after the blue "Ultra-Rugged Field PC" screen appears:
    • On Archer, press the Start (Windows logo) and Context (far right middle button with image of box containing four lines with second line highlighted) buttons.
    • On Allegro MX and TK6000 (Carlson Surveyor), press the Ctrl, Alt, and R keys.
  3. Release buttons and wait until you are asked to align the display (calibrate the touchscreen) to confirm success.
  4. After recovering files, perform a Clean Boot as instructed at the FAQ webpages below or restore the Windows registry from a previous backup.

Windows CE

In the Microsoft Windows CE operating system on older model Allegro Field PCs, performing a Restore System (Cold Boot) or Set Factory Defaults is similar to a Registry Clean in that these only effect the Windows registry and RAM storage memory, but not flash storage memory such as the internal "C_Drive".

But in cases when the Allegro is stuck at a boot screen (such as repeatedly scrolling through the operating system loading process), you can prevent the previously saved registry from loading (which could be causing these symptoms) following the below steps.

  1. Press and simultaneously hold the On/Off and Shift keys until the screen flashes off briefly, then release the On/Off key but keep pressing the Shift key until the Boot Menu screen appears.
  2. Select Cold Boot and press Enter.
  3. Immediately press and hold the Insert (Ins) key throughout the duration of the operating system loading process.


If you were successfully able to load the operating system, it is recommended to delete the previously saved registry by performing a Set Factory Defaults to ensure you do not again encounter issues while booting.