Draft:Setting BIOS date


 * Back to Draft:Windows build FAQ

This page lists instructions on how to set the BIOS date for each virtualization software. Setting the BIOS date is necessary for builds that include a timebomb (specifically Windows 95 build 216 and Windows 2000 build 1627 and above), as they more often than not will not boot or install on the current date.

86Box
Setting the BIOS date on 86Box will vary depending the system board that is used. However, before you set the BIOS date, you must ensure the "Time synchronization" setting on the machine configuration is set to "Disabled".

For most systems that have a BIOS installed on the system board, simply boot into the system setup during the power-on self-test (for example, the Award 486 clone uses the Del key to enter to setup) and there should be an option to change the system time in the BIOS. If there isn't a proper BIOS and a system reference/diagnostics disk must be used instead, then the disk should provide an option to change the system time on the board. Be sure to save the settings to the BIOS to set the time.

VirtualBox
Setting the BIOS date in VirtualBox requires calculating the amount of milliseconds between the current date and the compilation date of the build you want to install. The virtual machine should be turned off and VirtualBox should be closed before changing the BIOS date to avoid settings conflicts.


 * 1) Open a command prompt and make the VirtualBox installation directory the current directory (usually, run  ).
 * 2) Run  . Be sure to set the name of the virtual machine that will have the time sync disabled between the first set of quotation marks.
 * 3) Calculate the offset between the desired BIOS date and the current date. You can use the date calculator on the Windows Calculator and convert the amount of days to milliseconds (days * 86400000), but the faster way to do so is via the PowerShell command   and using the integer value in TotalMilliseconds (ignoring the values after the decimal).
 * 4) Run  . Use the same name of the virtual machine from step 2 and use the milliseconds value obtained from step 3.

VMware
VMware comes with its own BIOS/UEFI firmware that can be booted into, much like 86Box. However, installing VMware Tools will cause the time to sync back to the current date. To fully disable the time sync, the following lines needs to be added into the .vmx file of the virtual machine: time.synchronize.continue = "FALSE" time.synchronize.restore = "FALSE" time.synchronize.resume.disk = "FALSE" time.synchronize.shrink = "FALSE" time.synchronize.tools.startup = "FALSE"

To set the BIOS date, power onto the firmware (VM > Power > "Power On to Firmware") and set the BIOS date as you would in a normal BIOS. Be sure to save the settings to the BIOS to set the time.