Windows Evaluation Rearm for 360 days!

Windows Server evaluation editions run for a limited trial period before they either need converting to a licensed edition or shutting down. The built-in slmgr.vbs tool includes a rearm function that resets the countdown, buying extra time — useful for extending a lab or test environment without a license key on hand yet.

Checking Your Current Status

From an elevated Command Prompt, first check how much time is left and how many rearms remain:

slmgr /dlv

Rearming

slmgr /rearm

Restart the server after running this for the change to take effect. Each rearm resets the evaluation clock, but the number of times you can rearm a given installation is limited — slmgr /dlv shows the remaining rearm count for your specific build, so check that rather than assuming a fixed total, since it varies by Windows Server version and edition. Rearming is intended to give administrators breathing room to finish testing or procure a license — it isn’t a way to run evaluation software in production indefinitely, and Microsoft’s licensing terms for evaluation media should be reviewed if you’re using this outside of a lab.

How Many Times Can You Rearm? (Updated for 2026)

The mechanism itself is unchanged on current Windows Server evaluation media (Server 2022 and Server 2025 both use the same behaviour): each installation starts with a 180-day trial, and slmgr /rearm can be run up to 6 times, each extending the clock by another 180 days — a maximum evaluation lifespan of roughly 3.4 years before Windows refuses to rearm again (error 0xC004D307). slmgr /dlv remains the way to check exactly how many rearms you have left on a given installation rather than assuming the full count is still available, since some images inherit a partially-used rearm count from whatever process built them. No newer replacement for slmgr /rearm has been introduced — it’s still the current, supported way to extend an evaluation install in 2026. The one adjacent thing worth knowing about is the SkipRearm registry value used during Sysprep/imaging workflows, which prevents an automatic rearm from being silently consumed every time a reference image is captured — not something to reach for just to stretch out a trial, but useful context if a lab image’s rearm count is disappearing faster than expected.

Resources

• KMS
• guide