diff --git a/cmake/NSIS.template.in b/cmake/NSIS.template.in
index 7b52b7bcc..5e7b7542a 100644
--- a/cmake/NSIS.template.in
+++ b/cmake/NSIS.template.in
@@ -89,19 +89,7 @@ ${IfNot} ${Errors}
     Quit
 ${EndIf}
 
-ClearErrors
-${GetOptions} $9 "/PORTABLE" $8
-${IfNot} ${Errors}
-    StrCpy $PortableMode 1
-    StrCpy $0 $PortableDestDir
-${Else}
-    StrCpy $PortableMode 0
-    StrCpy $0 $NormalDestDir
-    ${If} ${Silent}
-        Call RequireAdmin
-    ${EndIf}
-${EndIf}
-
+; Detect reinstall mode first
 ClearErrors
 ${GetOptions} $9 "/R" $8
 ${IfNot} ${Errors}
@@ -112,14 +100,31 @@ ${Else}
     StrCpy $ReinstallMode 0
 ${EndIf}
 
-${If} $InstDir == ""
-    ; User did not use /D to specify a directory,
-    ; we need to set a default based on the install mode
-    StrCpy $InstDir $0
+; Only parse /PORTABLE for fresh installs
+${If} $ReinstallMode = 0
+    ClearErrors
+    ${GetOptions} $9 "/PORTABLE" $8
+    ${IfNot} ${Errors}
+        StrCpy $PortableMode 1
+        StrCpy $0 $PortableDestDir
+    ${Else}
+        StrCpy $PortableMode 0
+        StrCpy $0 $NormalDestDir
+        ${If} ${Silent}
+            Call RequireAdmin
+        ${EndIf}
+    ${EndIf}
 ${EndIf}
-Call SetModeDestinationFromInstdir
 
-; --- Detect portable install when using /R ---
+${If} $InstDir == ""
+    ${If} $ReinstallMode = 1
+        StrCpy $InstDir $NormalDestDir
+    ${Else}
+        StrCpy $InstDir $0
+    ${EndIf}
+${EndIf}
+
+; Detect portable installs during update from portable.dat
 ${If} $ReinstallMode = 1
     IfFileExists "$InstDir\portable.dat" 0 not_portable
         StrCpy $PortableMode 1
@@ -131,7 +136,11 @@ ${If} $ReinstallMode = 1
     portable_done:
 ${EndIf}
 
+Call SetModeDestinationFromInstdir
+
+; Only uninstall registered installs
 ${If} $ReinstallMode = 1
+${AndIf} $PortableMode = 0
     Call AutoUninstallIfNeeded
 ${EndIf}
 
@@ -157,10 +166,10 @@ FunctionEnd
 
 
 Function SetModeDestinationFromInstdir
-${If} $PortableMode = 0
-    StrCpy $NormalDestDir $InstDir
-${Else}
+${If} $PortableMode = 1
     StrCpy $PortableDestDir $InstDir
+${Else}
+    StrCpy $NormalDestDir $InstDir
 ${EndIf}
 FunctionEnd
 
diff --git a/cockatrice/src/interface/widgets/dialogs/dlg_update.cpp b/cockatrice/src/interface/widgets/dialogs/dlg_update.cpp
index f12550fa8..b0723f6d5 100644
--- a/cockatrice/src/interface/widgets/dialogs/dlg_update.cpp
+++ b/cockatrice/src/interface/widgets/dialogs/dlg_update.cpp
@@ -13,6 +13,9 @@
 #include <QVBoxLayout>
 #include <QtNetwork>
 #include <version_string.h>
+#if defined(Q_OS_WIN)
+#include <windows.h>
+#endif
 
 DlgUpdate::DlgUpdate(QWidget *parent) : QDialog(parent)
 {
@@ -219,9 +222,34 @@ void DlgUpdate::downloadError(const QString &errorString)
 void DlgUpdate::downloadSuccessful(const QUrl &filepath)
 {
     setLabel(tr("Installing..."));
-    // Try to open the installer. If it opens, quit Cockatrice
-    if (QProcess::startDetached(
-            QString("\"%1\" /R /D=\"%2\"").arg(filepath.toLocalFile(), QCoreApplication::applicationDirPath()))) {
+
+    const QString installer = filepath.toLocalFile();
+    const QString installDir = QDir::toNativeSeparators(QCoreApplication::applicationDirPath());
+    const QString args = QString("/R /D=\"%1\"").arg(installDir);
+
+    bool launched = false;
+
+    qInfo() << installer;
+    qInfo() << installDir;
+    qInfo() << args;
+
+#if defined(Q_OS_WIN)
+    SHELLEXECUTEINFOW sei = {};
+    sei.cbSize = sizeof(sei);
+    sei.fMask = SEE_MASK_NOCLOSEPROCESS;
+    sei.lpVerb = L"runas";
+    sei.lpFile = reinterpret_cast<LPCWSTR>(installer.utf16());
+    sei.lpParameters = reinterpret_cast<LPCWSTR>(args.utf16());
+    sei.nShow = SW_SHOWNORMAL;
+    launched = ShellExecuteExW(&sei);
+    if (launched && sei.hProcess) {
+        CloseHandle(sei.hProcess);
+    }
+#else
+    launched = QProcess::startDetached(installer, {"/R", QString("/D=%1").arg(installDir)});
+#endif
+
+    if (launched) {
         QMetaObject::invokeMethod(static_cast<MainWindow *>(parent()), "close", Qt::QueuedConnection);
         qCInfo(DlgUpdateLog) << "Opened downloaded update file successfully - closing Cockatrice";
         close();