diff --git a/iTALC.nsi.in b/iTALC.nsi.in
index c5350e79..916f1041 100644
--- a/iTALC.nsi.in
+++ b/iTALC.nsi.in
@@ -1,4 +1,5 @@
 !define DLLDIR "@MINGW_PREFIX@/bin"
+!define SYSTEM_DLLDIR "@MINGW_PREFIX@/@CMAKE_SYSTEM_PROCESSOR@-w64-mingw32/bin"
 !define APP_NAME "iTALC"
 !define COMP_NAME "iTALC Solutions Inc."
 !define WEB_SITE "http://italc.sf.net"
@@ -157,6 +158,7 @@ File "${DLLDIR}\libjpeg-9.dll"
 File "${DLLDIR}\libeay32.dll"
 File "${DLLDIR}\libssl32.dll"
 File "${DLLDIR}\libpng16-16.dll"
+File "${SYSTEM_DLLDIR}\libwinpthread-1.dll"
 # core components
 File "italc-${VERSION}\ica.exe"
 File "italc-${VERSION}\vnchooks.dll"
@@ -244,6 +246,7 @@ ExecWait '"$INSTDIR\ica.exe" -quiet -unregisterservice'
 # make sure the service is stopped and all file handles are released
 Sleep 2000
 Delete "$INSTDIR\ica.exe"
+Delete "$INSTDIR\libwinpthread-1.dll"
 Delete "$INSTDIR\zlib1.dll"
 Delete "$INSTDIR\libjpeg-9.dll"
 Delete "$INSTDIR\QtXml4.dll"