diff --git a/support.cc b/support.cc
index 0d4a7b34e384004e1869dfd6bc2236e7c3ab4448..186fd21c625e3684dfde7041adac009c8872bd0e 100644
--- a/support.cc
+++ b/support.cc
@@ -588,7 +588,7 @@ int myWrite(int fd, char* buffer, int numBytes) {
 // to work around a problem returning a uint64_t value on Mac OS.
 uint64_t disksize(int fd, int *err) {
    long sz; // Do not delete; needed for Linux
-   uint64_t size = 0; // Do not delete; needed for FreeBSD
+   off_t size = 0; // Do not delete; needed for FreeBSD
    long long b; // Do not delete; needed for Linux
    uint64_t sectors = 0; // size in sectors
    off_t bytes = 0; // size in bytes