I can't find a definitive answer to this, but I can see a lot of people are having the same issue.
I have setup magento 2.1.0 and all is going well. However the cron job fails on the update script.
I have the following error:
[2016-08-26 08:21:02] update-cron.ERROR: Cron readiness check failure!
Found non-writable paths: /home/<USER>/public_html/app/design/frontend/Magento [] []
Furthermore this file only exists under the pub/static folder and not under app/design/frontend. Its all very confusing.
I have run the permission changes from magento via ssh, I even tested this with cmod 777 but still to no avail. I have also tried running the cron job as both the user and root but still the same issue.
This is on a VPS running CPanel and WHM PHP version 5.6.24
Am I missing something stupid here or can anyone advise a way to fix this?
Best Answer
This is mainly to help others suffering with the same issue. This is what I have discovered.
There are 2 versions of Magento, the Magento download package which comes with composer installed and Magento from Github where you need to install composer.
The file path above wasn't there and doesn't need to be there because those files are stored under vendor.
My issue was mainly relating to the .setup_cronjob_status & .update_cronjob_status files under /var/ these are created on cron and store info.
It seems these store cache info. On deleting those files and all files under pub/static solved my issue.
I hope that helps someone else.