--- /dev/null
+When using [mathopd](http://www.mathopd.org) to serve ikiwiki, be careful of your Umask settings in the mathopd.conf.
+
+With `Umask 026` in mathopd.conf, editing pages would result in the following errors and a 404 page when the wiki tried to take me to the updated page.
+
+ append_indexes: cannot open .../[destdir]/[outputfile].html
+ open: Permission denied
+
+With `Umask 022` in mathopd.conf, editing pages works.
+
+Hopefully this prevents someone else from spending ~2 hours figuring out why this wouldn't work. ;)