Windows 95 build 73f

Windows 95 build 73f is a Milestone 5 (Preliminary Development Kit 2) build of Windows 95, which was found by BetaArchive user sunnyblueman in July 2014 along with builds 99 and 116. It is nearly identical to build 73g. The main difference is that this is an internal build and thus includes an internal version of the WinBug utility, while build 73g was released to external testers and thus features a different WinBug. It is safe to assume earlier compiles of this build (73a through 73e) also exist.

There are notable changes in this build compared to build 58s. Many aspects of Windows were ported to 32-bit, including the Cabinet shell (as stated by the new filename, ). The taskbar no longer functions as a folder by default. Instead, it now displays the running apps in a similar way to the modern taskbar. This build introduces the Briefcase special folder, which is meant to sync files between itself and another folder. It is also the first build to feature the "safe to shutdown" screen, serving as a reminder of when to turn off the PC without risk of possible data loss.

Since this build's installation media also comes with a SDK, it can be used to switch to a checked/debug compile of this build.

New features and changes
There are notable changes in this build compared to build 58s:

Shell features

 * Many aspects of Windows were ported to 32-bits. Most notably, the Cabinet shell is now 32-bit (as stated by its new filename, ).
 * The taskbar no longer functions as a folder by default. Instead, it now displays the running apps in a similar way to the modern taskbar. However, the folder view can be re-enabled by setting the tray settings to "View as Folder".
 * There is now an option on the first start menu to change the tray settings. The options is to set the view as either folder (works the same way as in build 58s) or as task view. It also includes an option to keep the taskbar on top of the screen and the ability to auto-hide the taskbar.
 * The minimize/maximize effect present in the previous build has been removed.
 * The title bar font and window font has been inverted from the previous build, and the title bar text now correctly has bold while the window font is no longer in bold.
 * The network login screen now corrects the "Windows for Workgroups" mention in the login message to "Chicago".
 * The third start button disables the "Quick Tips" option and merges "Window Contents..." and "Search for Help On... to "Help..."
 * This build introduces the Briefcase special folder, which is meant to sync files between itself and another folder. The Briefcase would remain in every Windows version until its removal in Windows 10 build 14942.
 * This build is the first 9x build to include a safe to shutdown screen, something that was previously present in the NT-branch of Windows during the time. Thus, the user does not have to wait at the shutdown screen before turning off the PC, and serves as a reminder of when to turn off the PC without risk of possible data loss.

Application features

 * Tracker and  has been removed and no longer load on startup.
 * WritePad is introduced in this build, which would later become WordPad. This became the replacement of Write from previous versions of Windows.
 * The Phone Dialer debuts in this build.
 * Media Player has a slightly updated interface, with the button designs being altered.
 * Music Box has been removed in this build.
 * This is the first build to include Microsoft WinPad. The version for this build's WinPad is 1.1602.
 * The WinBug utility has been changed for internal testers, and at start only gives an option to enter an email.

Control Panel features

 * The Sounds setting applet has been renamed to Multimedia and has been greatly redesigned. It also merges the MIDI Mapper and Sound Mapper setting applets that was present in previous versions of Windows.
 * The 386 Enhanced, Virtual Memory, and Window Metrics applets have been removed.
 * The Drivers setting applet has been merged with the Advanced System applet. The Advanced System applet also been greatly simplified to just one tab.
 * Network Setup and Modems both have new icons.
 * The System applet has removed the System Settings tab and the incomplete Startup Configurations setting.
 * There are new applets for Telephony (which requires a modem), and for Remote Administration and Network Security.
 * The tabs in the Disks applet now states the type of drive instead of the label name. It also removes the "Backup" task in the maintenance status.

Setup features

 * Setup has been massively overhauled, and starts to see some aspects of the RTM. It includes a new background, the NDA when starting setup, and settings to choose components to install.
 * The user can now add the user name and organization during setup. It also now requires a beta site ID and password, which would be the forerunner to product keys.

Beta Site ID and Password
This build is the earliest known build to require a Beta Site ID and password to install. An exhibit from Comes vs. Microsoft mentions that this feature was added in response to the original warez scene leak of build 58s. The protection works by having the last four digits of the password be derived from an MD4 hash of the beta site ID, the first four digits of the password, and a string in  resources. The fifth digit of the password is a check digit; if this is valid, the setup appears to continue but if the password used is for another build, setup will error before copying files with the "General error 57", a red herring that fooled the warez scene at the time, OSBetaArchive members a decade later, and BetaArchive members a few years after that.

There is a backdoor in ; an encrypted resource contains a list of network shares. If one of these shares exist, the user is not required to enter a Beta Site ID or Password. This feature was added for internal Microsoft testers, and when found by reverse engineers, made the protection easier to crack.

This protection was removed in build 311, but was reused briefly for early Internet Explorer 4.0 and Windows 98 builds (removed in the latter sometime before build 1351, but its   changed the network share list and password derivation string).

Start button and menu
Although this build still has three separate Start buttons and menus like build 58s, it already contains the necessary resources to enable a single unified Start menu (but not the single button), similar to that in build 81. A tutorial on how to remove the two extra buttons and display only the unified menu is available on BetaArchive.

Boot screen
The boot screen reports itself as being from November instead of August 1993.

Switching from free to checked/debug compile
To switch to the checked/debug compile, you will need to install the SDK, which is included in the SDK folder on the installation media. Launch setup and on the page where you select the components, select only "Debug binaries". After installation, select "Debug Chicago" in the "Chicago PDK" window and confirm that Windows is switching to Single DOS Application mode. After a restart, Windows will start, but a watermark appears at the bottom right of the screen saying "Debug Windows 4.00.73f". This means that you are now running the checked/debug compile of this build.

To switch back to the free compile, open Tasks by double-clicking the desktop. Then, open the Programs menu and select "Non-Debug Chicago" from the "Chicago PDK" folder. After another restart, you are back.

CAB32 loading error
On faster CPUs, this build has a problem loading  after setup. To allow the shell to load, edit  in the root of the system partition by changing the lines   and   to   and   respectively. You can do this by: When using one of the both former options, enter  into the command prompt to edit the file.
 * pressing F8 before the boot screen is displayed and confirming any line of  except for "Process Start-up command file", where you press N to prevent the shell to load.
 * using a DOS or Windows 9x bootdisk with a text editor on it, or
 * mounting the virtual hard disk image in Windows and editing the file there.

Black icon boxes
When using 32-bit color drivers intended for Windows 3.1x, installed through setup31.exe, after a reboot, the icons may turn into black boxes, this is due to icocache.dat issues, most likely the build has buggy handling of true color icons. Builds 73g and 81 have this issue too.

File differences
The following files have been introduced or removed compared to build 58s:


 * Most of the files are renamed, such as  now being named   and   now being named.