diff --git a/build/installer.nsh b/build/installer.nsh
new file mode 100644
index 0000000000..9a04aeea9e
--- /dev/null
+++ b/build/installer.nsh
@@ -0,0 +1,19 @@
+; Picked up by electron-builder as `<buildResources>/installer.nsh` (the NSIS `include` option).
+
+; A silent update of a per-machine install (`/S`, see installsSilently in electron/auto-updater.ts)
+; asks for UAC in the install section, by which time the app has already quit. Declining it
+; (error 1223) makes electron-builder's installer.nsi just Quit, so OpenScreen stays closed (#1461).
+; Elevate here instead, as the stock section would, and bring the app back if that fails. The
+; downloaded update stays cached, so the user can retry it.
+!macro customInit
+  ${if} ${Silent}
+  ${andIf} $hasPerMachineInstallation == "1"
+  ${andIfNot} ${UAC_IsAdmin}
+    !insertmacro UAC_RunElevated
+    ${if} $0 != 0
+    ${andIf} ${isForceRun}
+      ExecShell "open" "$perMachineInstallationFolder\${APP_EXECUTABLE_FILENAME}"
+    ${endIf}
+    Quit
+  ${endIf}
+!macroend