So no one else has to go down the troubleshooting path I went (Disable UAC, Disable Anti-Virus, Install as Admin, Install from Folder, etc.) here’s what worked for me to install Photoshop Elements 9 in Windows 10.
In an OwnCloud server if you change the permissions of an external drive to give r/w access (in my case chgrp www-data) and OwnCloud isn’t updating those permissions you can do this. In your MySQL database find your external storage in oc_storages and make note of the numeric id. Then run this query “Delete from oc_filecache where storage = numeric_id” replacing numeric_id with the one you found in the oc_storages table.
Ubuntu 14.04 Server