diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index d4aa207453..83e5b7cbb1 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -25155,7 +25155,7 @@ Change of this parameter will affect the layout of buttons in notification toast
       <key>Type</key>
       <string>Boolean</string>
       <key>Value</key>
-      <real>0</real>
+      <integer>0</integer>
     </map>
     <key>FSLookAtTargetMaxDistance</key>
     <map>
@@ -25168,6 +25168,19 @@ Change of this parameter will affect the layout of buttons in notification toast
       <key>Value</key>
       <real>1</real>
     </map>
+    <key>FSResetUIScaleOnFirstRun</key>
+    <map>
+      <key>Comment</key>
+      <string>Resets the UI scale factor on first run due to changed display scaling behavior</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>1</integer>
+      <key>Backup</key>
+      <integer>0</integer>
+    </map>
   </map>
 </llsd>
 
diff --git a/indra/newview/llviewerwindow.cpp b/indra/newview/llviewerwindow.cpp
index 9641a1f935..f07c603d44 100644
--- a/indra/newview/llviewerwindow.cpp
+++ b/indra/newview/llviewerwindow.cpp
@@ -1841,6 +1841,17 @@ LLViewerWindow::LLViewerWindow(const Params& p)
 	LLCoordScreen scr;
     mWindow->getSize(&scr);
 
+	// <FS:Ansariel> Reset UI scale factor on first run if OS's display scaling is not 100%
+	if (gSavedSettings.getBOOL("FSResetUIScaleOnFirstRun"))
+	{
+		if (mWindow->getSystemUISize() != 1.f)
+		{
+			gSavedSettings.setF32("UIScaleFactor", 1.f);
+		}
+		gSavedSettings.setBOOL("FSResetUIScaleOnFirstRun", FALSE);
+	}
+	// </FS:Ansariel>
+
 	// Get the real window rect the window was created with (since there are various OS-dependent reasons why
 	// the size of a window or fullscreen context may have been adjusted slightly...)
 	F32 ui_scale_factor = llclamp(gSavedSettings.getF32("UIScaleFactor"), MIN_UI_SCALE, MAX_UI_SCALE) * mWindow->getSystemUISize();