Many of you on PC EU have been running into issues over the past 24 hours, such as guild and friends lists not appearing, among other issues. This morning, we adjusted the guild history from 10 days to 5 days, and we also disabled the ability for addons to read guild history from the server. Note this will break some popular addons such as Master Merchant - we recommend turning off any addons that may utilize this feature. Both of these were done on PC NA and EU.
These changes should help the issues many of you have been running into, but we'll continue to monitor and make additional changes as necessary.