I just updated to the Insider Program, and the memory graph is blank.

Because only Task Manager’s memory graph became blank immediately after an Insider build, while the other performance graphs still work, this is more consistent with a Task Manager or build regression than missing RAM. Install the newest Insider update and Microsoft Store app updates, then reopen Task Manager. Confirm that Windows reports the expected installed and usable memory in Settings or System Information. Next run DISM /Online /Cleanup-Image /RestoreHealth followed by sfc /scannow from an elevated terminal, and test from a new local profile to exclude damaged per-user state. Check the release notes for your exact build for known Task Manager issues. Submit Feedback Hub data with the full build number, screenshot, reproduction steps, and diagnostic recording. Rolling back is reasonable only if the problem affects normal operation and the recovery option remains available; Windows generally keeps that option for a limited period after an upgrade.