After a Magento upgrade, refreshing the Magento cache gives a blank white error screen.

Hold on Cowboy

This blog post is pretty old. Be careful with the information you find in here. It's likely dead, dying, or wildly inaccurate.

So you’ve successfully upgraded Magento and now you’re rolling live on the new code and db…. You did remember to save a copy DB incase you have to back track?

You go to the Cache Management page and try to refresh the cache (just because you want to cover all your bases). After clicking the button with confidence you get a white screen, no alerts, no friendly exception report, just white.

Checklist. 1. Is your var/ directory writable by the web server? 2. Is your app/etc/use_cache.ser file writable by the web server?

That second one was the culprit this time, why is it that permissions are the problem 11 out of 10 times?

Did this help you out? It took me a few days to piece together all this information together, I hope this saves you some time (who knows, maybe the future me will be thankful I wrote this down). Let me know your thoughts.