How to Install CAB Files on Windows Mobile 6.5

In Windows Mobile 6.5, Cabinet (.cab) files served as the primary package format for distributing and installing software directly on mobile devices. This article explains how .cab files operated within the Windows CE architecture, how the operating system processed these packages, and the mechanisms used to deploy and remove applications without relying on a host PC.

The Role of .CAB Files in Windows Mobile

A .cab file in Windows Mobile 6.5 was a compressed archive containing all the binaries, assets, and metadata required to install an application. Unlike desktop Windows installers, which often used executable setup files (.exe), Windows Mobile relied on standardized .cab archives that adhered to the Microsoft Windows CE CabWiz specifications. Inside the archive was an instructional file—typically named _setup.xml—that specified target installation directories, registry keys to create or modify, and application shortcuts.

Transferring the File to the Device

Before an installation could begin, the .cab file had to be transferred to the device. Users accomplished this through several methods:

  • Direct Download: Downloading the file directly through the mobile Internet Explorer browser or third-party browsers like Opera Mobile.
  • Storage Card: Copying the file to a microSD card on a computer and inserting it into the phone.
  • PC Synchronization: Transferring the file via a USB connection using ActiveSync (on Windows XP) or Windows Mobile Device Center (on Windows Vista and Windows 7).
  • Wireless Transfer: Receiving the file over Bluetooth from another device.

The Installation Process via WCELOAD

Once the .cab file resided in the device's file system, the user navigated to it using the native File Explorer and tapped the file. This action initiated the built-in system installer, wceload.exe (Windows CE Load).

  1. Target Selection: wceload.exe read the archive header and prompted the user to select an installation target: either the device's internal storage (Device Memory) or an external storage card (microSD).
  2. File Extraction: The installer extracted the compressed files and placed them into designated directories, typically under \Program Files\[Application Name]\.
  3. Registry Configuration: The utility updated the Windows Mobile registry (under HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER) with necessary configuration data, file associations, and component registrations.
  4. Shortcut Generation: wceload.exe placed a shortcut (.lnk file) in \Windows\Start Menu\Programs, making the application accessible from the Windows Mobile 6.5 honeycomb Start menu.

Post-Installation File Deletion

A defining characteristic of the Windows Mobile 6.5 installation mechanism was automatic deletion. By default, once wceload.exe finished a successful installation, it automatically erased the source .cab file to conserve the device's limited internal storage.

To prevent this automatic deletion, users had to set the .cab file's attributes to "Read-Only" using a third-party file manager (such as Resco Explorer) before running it, or keep a backup copy on a PC or secondary folder.

Software Removal

When wceload.exe installed an application, it logged all file placements and registry edits into an uninstall routine. Users could remove software cleanly by opening Settings, navigating to the System tab, selecting Remove Programs, and choosing the application from the list. The OS would then reverse the registry changes, remove the shortcuts, and delete the associated program directory.