Understand won't start / won't run on my OS

Understand does not block startup by OS version

There's no runtime OS-version check that refuses to launch. So "won't run on " is almost always a missing/incompatible system dependency (shared libraries, glibc/Qt runtime on Linux) or a broken install — not Understand deliberately rejecting the OS.

Check, in order

1. Confirm the build and platform match. You need the build for your OS/architecture. Check your OS version against the supported OS table — if you're on an older OS than what the current build targets, contact support for a build with an earlier baseline rather than troubleshooting further. Otherwise, note your exact OS + version and the Understand build number (from an install that does run, or the installer) — you'll need these for support.
2. Linux: missing shared libraries. Launch understand from a terminal and read the error. A error while loading shared libraries: ... or glibc-version message points at the missing dependency to install. Older distributions may lack the runtime libraries a newer build needs. See installing Understand on Linux for full instructions. If the message is an Understand message rather than a loader one, look it up in the error and warning message index.
3. macOS: "can't be opened because it is from an unidentified developer." This is Gatekeeper, not a real problem with the app — Understand is signed and notarized, but it loads some libraries from outside the app bundle, which Gatekeeper can mis-flag on first run. Right-click the app and choose Open, then confirm; this clears the warning for subsequent launches. See install Understand for the full first-run steps.
4. Windows: missing Visual C++ runtime. An error naming a missing VCRUNTIME*.dll or MSVCP*.dll means the Visual C++ Redistributable didn't get installed — the Understand installer runs it silently as part of setup, but a locked-down/imaged machine can block that step. Install the redistributable yourself (search "Microsoft Visual C++ Redistributable x64" from Microsoft) and relaunch.
5. Rule out corrupt settings. If Understand starts but immediately misbehaves (or hangs during startup), try resetting Understand to default settings.
6. Reinstall cleanly. Remove the install and reinstall from a fresh download in case files are corrupt or partial.
7. Windows: if it starts then crashes, see Understand crashed for the crash log and reporter.

Get help

Send SciTools your OS + version, the build number, and the terminal output from step 2 (or the crash log). See contact support.