It seems that some people end up on a rogue chain after the update, please verify your block number with the number at the RIGHT BOTTOM of the explorer page: http://explorer.helix-crypto.com/

If your wallet is at different block, check your wallet if you're running v1.2.0(https://github.com/ProjectHelixCoin/helix/releases). If you are, shut down your wallet -> go to your data folder (where your wallet.dat is) -> Remove folder "blocks" and "chainstate" and let it sync up again.

In order to skip a large part of the syncing process, you could also use our bootstrap file:
https://we.tl/t-RFmwj1o7xG

Instead of starting your wallet after deleting the "blocks" and "chainstate" folder, put the bootstrap.dat in the same folder as your wallet.dat is in. Now launch your wallet and it should tell you "importing blocks from disk". Now simply wait till it finishes and verify your block count again with the explorer count.

For those who used the masternode script (https://github.com/ProjectHelixCoin/vps) and also have to resync those:

Stop your wallets by typing
systemctl stop helix_n*
Then remove your data directories (your configs will stay as they are at a different location)
sudo rm -r /var/lib/masternodes/helix*/blocks
sudo rm -r /var/lib/masternodes/helix*/chainstate
And restart your masternodes again with
sudo /usr/local/bin/activate_masternodes_helix
(If it gives a single mn error, start it seperately via "systemctl restart helix_n<your nr>")
Now wait till they are synced up again and then start them via your controller wallet

Those who used this vps script: https://github.com/ProjectHelixCoin/Masternode-Setup-Helix

Stop your mn
helix-cli stop
Remove the blocks and chainstate folders
sudo rm -r ~/.helix/blocks
sudo rm -r ~/.helix/chainstate
Restart your wallet and let it sync up
helixd -daemon
Wait for your wallet to be synced
helix-cli getblockcount
Once synced, start your masternodes in your controller wallet