diff --git a/programs/fileio.c b/programs/fileio.c
index d72879d6..76243950 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -771,9 +771,10 @@ static void FIO_adjustMemLimitForPatchFromMode(FIO_prefs_t* const prefs,
                                     unsigned long long const maxSrcFileSize)
 {
     unsigned long long maxSize = MAX(prefs->memLimit, MAX(dictSize, maxSrcFileSize));
+    unsigned const maxWindowSize = (1U << ZSTD_WINDOWLOG_MAX);
     assert(maxSize != UTIL_FILESIZE_UNKNOWN);
-    if (maxSize > UINT_MAX)
-        EXM_THROW(42, "Can't handle files larger than %u GB\n", UINT_MAX/(1 GB) + 1);
+    if (maxSize > maxWindowSize)
+        EXM_THROW(42, "Can't handle files larger than %u GB\n", maxWindowSize/(1 GB));
     FIO_setMemLimit(prefs, (unsigned)maxSize);
 }