After opening Task View with a keyboard shortcut, the arrow keys don't work to switch between views

Restarting File Explorer rules out only a transient shell issue; it does not confirm that Task View’s keyboard focus works. Microsoft documents Win + Tab to open Task View and Win + Ctrl + Left Arrow or Win + Ctrl + Right Arrow to switch directly between virtual desktops. Use those shortcuts as the immediate workaround. Inside Task View, test Tab and Shift + Tab to move focus, followed by Enter, because arrow keys may not receive focus until a control is selected. Install Windows updates, then test another keyboard and another user profile. Temporarily disable keyboard-remapping, accessibility, shell-customization, or hotkey utilities that could intercept navigation keys. If arrows still cannot select thumbnails, record the Windows edition and build with winver and file a Feedback Hub problem while reproducing it, with a recording and input details. That is safer than registry changes for behavior Microsoft does not document as configurable.