diff --git a/doc/contributions.txt b/doc/contributions.txt
index 24909e6c4017b353c922953ab801004a359fec96..a73bd10295bdbb8989189a2fe63b7c213cf3c747 100755
--- a/doc/contributions.txt
+++ b/doc/contributions.txt
@@ -222,6 +222,7 @@ Ansariel Hiller
 	MAINT-8085
 	MAINT-8723
 	SL-10385
+	SL-10891
 Aralara Rajal
 Arare Chantilly
 	CHUIBUG-191
diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index 09d784556723f8084af28c09de1f2393320af372..916781e85bdb35a5284ea45e3cd817afbd736b64 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -16310,6 +16310,19 @@
       <key>Value</key>
       <integer>0</integer>
     </map>
+    <key>ResetUIScaleOnFirstRun</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 a1edbf6addde539d080cf6b26d64b15843515c4d..51969a70916fa69ba2510e83e2a719efdf57cb67 100644
--- a/indra/newview/llviewerwindow.cpp
+++ b/indra/newview/llviewerwindow.cpp
@@ -1763,12 +1763,19 @@ LLViewerWindow::LLViewerWindow(const Params& p)
 	LLCoordScreen scr;
     mWindow->getSize(&scr);
 
+    // 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("ResetUIScaleOnFirstRun", FALSE);
+    }
+
 	// 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);
-#if LL_DARWIN
-    ui_scale_factor *= mWindow->getSystemUISize();
-#endif
+	F32 ui_scale_factor = llclamp(gSavedSettings.getF32("UIScaleFactor"), MIN_UI_SCALE, MAX_UI_SCALE) * mWindow->getSystemUISize();
 	
 	mDisplayScale.setVec(llmax(1.f / mWindow->getPixelAspectRatio(), 1.f), llmax(mWindow->getPixelAspectRatio(), 1.f));
 	mDisplayScale *= ui_scale_factor;
@@ -5341,11 +5348,7 @@ F32	LLViewerWindow::getWorldViewAspectRatio() const
 
 void LLViewerWindow::calcDisplayScale()
 {
-    F32 ui_scale_factor = llclamp(gSavedSettings.getF32("UIScaleFactor"), MIN_UI_SCALE, MAX_UI_SCALE);
-#if LL_DARWIN
-    ui_scale_factor *= mWindow->getSystemUISize();
-#endif
-
+	F32 ui_scale_factor = llclamp(gSavedSettings.getF32("UIScaleFactor"), MIN_UI_SCALE, MAX_UI_SCALE) * mWindow->getSystemUISize();
 	LLVector2 display_scale;
 	display_scale.setVec(llmax(1.f / mWindow->getPixelAspectRatio(), 1.f), llmax(mWindow->getPixelAspectRatio(), 1.f));
 	display_scale *= ui_scale_factor;