diff --git a/lib/config/folderconfiguration.go b/lib/config/folderconfiguration.go
index c8e327a54..6f2e0ea61 100644
--- a/lib/config/folderconfiguration.go
+++ b/lib/config/folderconfiguration.go
@@ -62,11 +62,11 @@ func (f FolderConfiguration) ModTimeWindow() time.Duration {
 		if usage, err := disk.Usage(f.Filesystem().URI()); err != nil {
 			dur = 2 * time.Second
 			l.Debugf(`Detecting FS at "%v" on android: Setting mtime window to 2s: err == "%v"`, f.Path, err)
-		} else if usage.Fstype == "" || strings.Contains(strings.ToLower(usage.Fstype), "fat") || strings.Contains(strings.ToLower(usage.Fstype), "msdos") {
+		} else if strings.HasPrefix(strings.ToLower(usage.Fstype), "ext2") || strings.HasPrefix(strings.ToLower(usage.Fstype), "ext3") || strings.HasPrefix(strings.ToLower(usage.Fstype), "ext4") {
+			l.Debugf(`Detecting FS at %v on android: Leaving mtime window at 0: usage.Fstype == "%v"`, f.Path, usage.Fstype)
+		} else {
 			dur = 2 * time.Second
 			l.Debugf(`Detecting FS at "%v" on android: Setting mtime window to 2s: usage.Fstype == "%v"`, f.Path, usage.Fstype)
-		} else {
-			l.Debugf(`Detecting FS at %v on android: Leaving mtime window at 0: usage.Fstype == "%v"`, f.Path, usage.Fstype)
 		}
 	}
 	return dur