diff --git a/OpenFilesScreen.c b/OpenFilesScreen.c
index 787e17b9..4256575c 100644
--- a/OpenFilesScreen.c
+++ b/OpenFilesScreen.c
@@ -226,7 +226,7 @@ static OpenFiles_ProcessData* OpenFilesScreen_getProcessData(pid_t pid) {
       struct stat st;
       if (stat(filename, &st) == 0) {
          char fileSizeBuf[21]; /* 20 (long long) + 1 (NULL) */
-         xSnprintf(fileSizeBuf, sizeof(fileSizeBuf), "%"PRIu64, st.st_size); /* st.st_size is long long on macOS, long on linux */
+         xSnprintf(fileSizeBuf, sizeof(fileSizeBuf), "%"PRIu64, (uint64_t)st.st_size); /* st.st_size is long long on macOS, long on linux */
          free_and_xStrdup(&item->data[fileSizeIndex], fileSizeBuf);
       }
    }