NirSoft's RunAsDate is a small, free tool that lets you run applications using a different time and date stamp than your Windows system, yet without changing your Windows system time. It can change the date and time of multiple programs running simultaneously, each with different time and date settings. We can think of several reasons for wanting to do that (debugging log files, for example) so in any case, it's a useful capability to have around. However, it's not designed to extend shareware trial periods, which use different means of keeping track of such things.
Both 32-bit and 64-bit downloads of RunAsDate are available; neither will run 16-bit DOS programs, though. We saved this portable freeware to a regular directory, but you can save it on a USB drive and run it on any compatible Windows machine, if you prefer. The program's interface is hardly bigger than a music player. It has three entry fields, Application to run, Parameters, and Create Desktop Shortcut, plus a Date/Time field with pop-out calendar and time spinner. The program offers check boxes for two options, Move the time forward according to the real time, which is selected by default, and Immediate Mode, which changes the date immediately when the program starts. The Immediate Mode substitutes the altered date and time as soon as a program's kernel starts loading instead of waiting for it to fully load. That prevents some programs from receiving the real system date and time before RunAsDate can change it. We had limited success with Immediate Mode, which can cause some programs to crash, especially if they're written in .NET. There's no Help file, but the program's Web site contains useful information, instructions, version history, and more.
RunAsDate is supereasy to use. We browsed to a popular freeware system information utility that displays the system time and date on its interface and selected its executable (you can enter the path in the Parameters field if you prefer). Next we changed the time and date using the Date/Time controls. When we were ready, we pressed Run. The program started with the altered time and date displayed. Not every program we tried responded to RunAsDate, and we had better luck with the 32-bit version than the 64-bit download. Still, the download is another unique and useful tool from NirSoft.