The items in the guild bank seem to be gone.
This morning I noticed that I couldn’t get some of the items in the bank tabs. 6 out of 7 tabs were reset after the server reset just now. Since I only have my own characters in the guild bank, there is no possibility for someone else to get it.
If you can still see your items in your guild banks, empty your bank immediately. When you start having trouble putting items in the bank or when it’s your turn to reset 
all your items will disappear.
I can confirm my entire personal guild bank (6tabs) full of valuable items was wiped.
Adding to this, there is nothing in the logs, no withdrawn items, and nobody except me has access to the vault.
Checked a few guild vaults now on Ravencrest - EU, including my main raiding guild with 250 members. Seems to all have been wiped of items. Blizz needs to reroll the servers fast.
Peronal guild bank affected:
Boebank - Ravencrest EU wiped
Social guilds I saw got wiped:
Sinbreakers - Ravencrest EU wiped
Malevolent Squad - Ravencrest EU wiped
My personal guild bank where only I have access to, my main raiding guild bank, all fully wiped of items. Nothing withdrawn showing in logs.
Ravencrest - EU
Need a server reroll fast.
Upon checking my Warband Bank, I saw that all my tabs were gone. This wasn’t the case earlier today. Please restore the bank, including all my precious stored items!
Guild banks are wiped too, trying to get attention to this issue before its too late.
Everyone check your personal banks, guild, warband etc and report the issue if yours is wiped too.
seems to be solved now, luckily.
Many guild banks are still wiped, that issue is not solved.
Thank you for the reports, we have informed the relevant parties now for additional investigation! 
Just to be on the safe side… can I ask any of you to try adding one random item (possibly nothing precious 
) to any of the affected bank(s), close and reopen said bank and check if anything changes?
It works to add an item, and the item is still there after closing and reopening the vault. I logged out and logged in and the item is still there.
I checked my other personal guild vaults, and they are not wiped. Only my main guild bank is wiped (Boebank - Ravencrest), which is the character I tried to log into during the server/realm issues earlier today, im thinking it might correlate.
-The bank of a raiding guild im in called Sinbreakers on Ravencrest - EU has been wiped (250 members)
-The bank of a social guild im in called Malevolent Squad on Ravencrest - EU has been wiped (90 members)
Confirmed, Guild Bank still empty, all tabs.
Personal Bank, Reagent Bank and Warband Bank OK.
I have same issue. %90 of my guild bank items are missing. Guild bank log is not showing any of those items as withdrew.
Can confirm about 80-90% of our Guild bank has been wiped as well, no withdraws shown.
The last logs were deposits however the tab remains empty.
Most banks wiped here too. Logs unaffected. Personal banks and Warband bank are okay. Still evaluating the full extent of the damage since I’ve got 11 banks, but so far, out of 5-6 checked, only one seems to be unaffected.
Guild banks emptied here too. All but 2 tabs completly wiped clean
What worries me is that, aside from a reply here (thanks, Felranys) and a couple merged threads, Blizzard is completely silent about this. No CS Twitter post about this, no official statement, nothing. I fear that this will be swept under the rug and the closest we’ll get to a solution is a “whoops sorry hahah”, and that’s if we ever hear again from them about this topic. Since relatively few people have been affected and no big guilds have complained, chances are we won’t be getting our items back.
I trust Blizzard about this issue. Ofcourse if it can’t be fixed, I will need 4x Epic Edition to compansate my losses 
. I hope they can fix it quick, I have things in my guildbank that needs to go this week.
Happening on NA realms too. Maybe we get more updates in those threads. If youve got an NA account make a post in that thread so blizzard maybe starts prioritizing this more.