When trying to copy a file from your Vault mounted with WebDAV you receive the error message "Can't read from source file or disk"
The PHP memory limit on the appliance is set to 128MB, when copying large files this causes a memory allocation error.
You can set this value higher if you depend on WebDAV to accessing the data.
Edit file: # /etc/php.ini
Once done you need to restart the webserver for the changes to take effect:
# service httpd restart
Note: You may need to change the memory setting of your VM appliance configuration if your PHP memory_limit value exceeds this setting.