Zcash server won't start

Hi, haven’t started my VirtualBox Ubuntu for like a year or two, because that’s where my Zcash wallet is located. I’m sure everything is outdated, but I’m not experienced with Ubuntu so I don’t know what to do.

What I do is run the commands (this has always worked in the past):
cd zcash
./src/zcashd -daemon

then it says:
Zcash server starting
zcashd: wallet/wallet.cpp:1780: int CWallet::ScanForWalletTransactions(CBlockIndex*, bool): Assertion `pcoinsTip->GetAnchorAt(pindex->hashAnchor, tree)’ failed.

And if I try to open ZCash Swing Wallet UI 0.34 (beta), it gives wallet communication error which basically says “make sure that zcashd server has started”. Obviously makes sense to me, so how can I connect to the server?

Looking around the web, someone suggested to add line rpcallowip= in the zcash.conf, but no luck so far.

You should upgrade as per https://github.com/zcash/zcash/wiki/1.0-User-Guide#upgrading as you are going to need to do this regardless with Overwinter activating tomorrow. Just make a backup of wallet.dat first.