diff --git a/FAQ.md b/FAQ.md
index 969ba7c..9131d47 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -17,3 +17,29 @@ Usually the logs are collected during a long period of time span. Let's say each
     /logs/2015-01-02.log
     /logs/2015-01-03.log
     /logs/2015-01-04.log
+
+## Mount Filer
+### weed mount error after restarting
+
+If you mount SeaweedFS filer on MacOS, sometimes when restarting "weed mount -dir xxx", you may see this error:
+
+> mount helper error: mount_osxfuse: mount point xxx is itself on a OSXFUSE volume
+
+To fix this, do mount:
+
+> chris:tmp chris$ mount
+> /dev/disk1s1 on / (apfs, local, journaled)
+> devfs on /dev (devfs, local, nobrowse)
+> /dev/disk1s4 on /private/var/vm (apfs, local, noexec, journaled, noatime, nobrowse)
+> map -hosts on /net (autofs, nosuid, automounted, nobrowse)
+> map auto_home on /home (autofs, automounted, nobrowse)
+> map -fstab on /Network/Servers (autofs, automounted, nobrowse)
+> /dev/disk2 on /Volumes/FUSE for macOS (hfs, local, nodev, nosuid, read-only, noowners, quarantine, mounted by chris)
+> weed@osxfuse0 on /Users/chris/tmp/mm (osxfuse, local, nodev, nosuid, synchronous, mounted by chris)
+
+The last line shows the folder that already mounted something. Need to unmount it first.
+
+> chris:tmp chris$ umount weed@osxfuse0
+
+That should be it!
+