Open-source software won't install on Windows 11? Check these three gates first

The same installer that was uneventful on Windows 10 can stall on Windows 11 for reasons that have nothing to do with the software.

Verified on Windows 11 and Ubuntu 24.04; other platforms follow the same shape.

The three usual suspects

1. Memory integrity (core isolation)

Settings → Privacy & security → Windows Security → Device security → Core isolation. Some hypervisors and drivers need it off to install; re-enable afterward.

2. SmartScreen / unknown publisher

"Run anyway" clears one prompt. If the file came off the network, also right-click → Properties → Unblock, or behavior gets strangely inconsistent.

3. Source and privilege

Non-store binaries should be signed. After extraction, a batch of executables flagged by Mark-of-the-Web suggests unblocking the archive before running anything.

Finding out who blocked it

Event Viewer beats guessing:

Get-WinEvent -LogName "Microsoft-Windows-Windows Defender/Operational" -MaxEvents 20

A Defender entry means security policy; no entry plus an installer error points at the installer's own log and its prerequisites (VC++ runtime, .NET version).

Frequent innocent causes: missing VC++ Redistributable, paths with spaces or non-ASCII characters, and registry locks left by a prior uninstall.

After the install

Turn every temporary security exception back on. An installer should not permanently downgrade the machine.
Record exactly what you changed — the next OS upgrade or rebuild will need the same exception list.
Leave MOTW unblock as-is for daily use; it does not affect normal operation.

Related resource

For the "can I re-verify this later" half of the workflow I keep GitVaults (https://gitvaults.com) open: every entry carries the upstream link, file size, and SHA-256, with a cloud mirror as the reachability fallback.

rtk ai rtk 0 49 0 → https://gitvaults.com/download/2026/09/11/rtk-ai-rtk-0-49-0/en

That page puts version, architecture, and digest on one screen — download, compare the hash, then install. The catalog has another hundred-plus entries in the same format if you need neighbors.