diff --git a/net/base/platform_mime_util_mac.mm b/net/base/platform_mime_util_mac.mm
index 6ca45512611247..a564e65c53f5ec 100644
--- a/net/base/platform_mime_util_mac.mm
+++ b/net/base/platform_mime_util_mac.mm
@@ -177,10 +177,14 @@ - (NSArray*)extensionsForMIMEType:(NSString*)mimeType;
                                            nullptr));
       if (types) {
         for (CFIndex i = 0; i < CFArrayGetCount(types); i++) {
-          base::apple::ScopedCFTypeRef<CFArrayRef> extensions_list(
-              UTTypeCopyAllTagsWithClass(base::apple::CFCast<CFStringRef>(
-                                             CFArrayGetValueAtIndex(types, i)),
-                                         kUTTagClassFilenameExtension));
+          base::apple::ScopedCFTypeRef<CFArrayRef> extensions_list;
+          if (@available(macOS 10.10, *)) {
+            extensions_list.reset(
+                UTTypeCopyAllTagsWithClass(
+                    base::apple::CFCast<CFStringRef>(
+                        CFArrayGetValueAtIndex(types, i)),
+                    kUTTagClassFilenameExtension));
+          }
           if (!extensions_list) {
             continue;
           }