diff --git a/Installer/Installer.iss b/Installer/Installer.iss
index 9ccc92ce..554a5310 100644
--- a/Installer/Installer.iss
+++ b/Installer/Installer.iss
@@ -7,6 +7,7 @@
 
 [Setup]
 AppId={{A5AF4C34-70A7-4D3B-BA18-E49C0AEEA5E6}
+AppMutex=DBDE24E4-91F6-11DF-B495-C536DFD72085-switcheroo
 AppName={#MyAppName}
 AppVerName={#MyAppName} v{#MyAppVer}
 AppPublisher={#MyAppPublisher}