diff --git a/stepmania/src/arch/MemoryCard/MemoryCardDriverThreaded_MacOSX.cpp b/stepmania/src/arch/MemoryCard/MemoryCardDriverThreaded_MacOSX.cpp
index bbe2e9730b..1e1c10080d 100644
--- a/stepmania/src/arch/MemoryCard/MemoryCardDriverThreaded_MacOSX.cpp
+++ b/stepmania/src/arch/MemoryCard/MemoryCardDriverThreaded_MacOSX.cpp
@@ -201,7 +201,7 @@ void MemoryCardDriverThreaded_MacOSX::GetUSBStorageDevices( vector<UsbStorageDev
 			
 			LOG->Trace( "Found memory card at path: %s.", fs[i].f_mntonname );
 			usbd.SetOsMountDir( fs[i].f_mntonname );
-			usbd.iVolumeSizeMB = (uint64_t(fs[i].f_blocks) * fs[i].f_bsize) >> 20;
+			usbd.iVolumeSizeMB = int( (uint64_t(fs[i].f_blocks) * fs[i].f_bsize) >> 20 );
 		
 			// Now we can get some more information from the registry tree.
 			usbd.iBus = GetIntProperty( device, CFSTR("USB Address") );