diff --git a/src/3rdparty/zlib/qtpatches.diff b/src/3rdparty/zlib/qtpatches.diff
index 105dda967cf..98a7b2c2059 100644
--- a/src/3rdparty/zlib/qtpatches.diff
+++ b/src/3rdparty/zlib/qtpatches.diff
@@ -26,12 +26,14 @@ diff -ruN orig/gzguts.h src/gzguts.h
 +#  ifndef _CRT_NONSTDC_NO_DEPRECATE
 +#    define _CRT_NONSTDC_NO_DEPRECATE
 +#  endif
++// disable warnings like '=': conversion from 'size_t' to 'unsigned int', possible loss of data
++#  pragma warning(disable: 4267)
 +#endif
 +
  #ifdef _LARGEFILE64_SOURCE
  #  ifndef _LARGEFILE_SOURCE
  #    define _LARGEFILE_SOURCE 1
-@@ -12,6 +21,15 @@
+@@ -12,6 +23,15 @@
  #  endif
  #endif
  
diff --git a/src/3rdparty/zlib/src/gzguts.h b/src/3rdparty/zlib/src/gzguts.h
index 20de7cb4cea..055de5100f7 100644
--- a/src/3rdparty/zlib/src/gzguts.h
+++ b/src/3rdparty/zlib/src/gzguts.h
@@ -10,6 +10,8 @@
 #  ifndef _CRT_NONSTDC_NO_DEPRECATE
 #    define _CRT_NONSTDC_NO_DEPRECATE
 #  endif
+// disable warnings like '=': conversion from 'size_t' to 'unsigned int', possible loss of data
+#  pragma warning(disable: 4267)
 #endif
 
 #ifdef _LARGEFILE64_SOURCE