I recently updated to the latest version of HA 2021.11. After doing this, I noticed my “Default” lovelace page (that shows every entity) would just appear as a completely blank white page along with 2 of my other 7 custom pages that I use for tablets around the house. This happens across different browsers and devices. What is strange is that occasionally, all of the icons will come back as if nothing has happened but later disappear again.
In troubleshooting this, it seems that if I remove the “media control card” from a lovelace dashboard, the page loads up perfectly fine again. However, I cannot remove this from my “Default” page since it loads all entities, so that is still a problem. If I re-add the “media control card” to a page, the page again shows up completely blank.
I did not see this is any breaking change documentation. Is anyone else having this problem?
THANK YOU! My All Entities dashboard has been blank for months and I couldn’t figure out what was causing it. I disabled my Sonos integration and everything reappeared! I re-enabled the Sonos integration, restarted the server and everything stayed (the interesting thing is that anything that uses a media player does not show up in the All Entities dashboard even after re-enabling which I am completely fine with). So maybe try disabling the integration or devices that are using the media player, restart the server, then re-enabled them.
After doing more troubleshooting and with some help from others, I was able to figure out that a custom card was causing the problems (mine happened to be the Atomic Calendar Revive card). Here is the GitHub issue that I initially had where the solution came from: https://github.com/home-assistant/frontend/issues/10605