We have been working the with NEO team for the past few months to address some wallet stability and performance issues.
Version 2.6 of NEO was recently released a week ago on January 14th which is meant to address our concerns.
In this upgrade process, the wallet format has been changed from SQLite DB3 to a JSON format. We began this wallet conversion process when the new release was available, however there was no progress indicator and after 1 week, the conversion had still not completed. The NEO team has advised us to stop the the wallet conversion process and they will add more development work to the wallet conversion process so that it completes in a more timely basis.
Since they could not provide an ETA on the wallet conversion work, the NEO team has also decided to support the SQLite DB3 wallet format as well which requires less development work. Their next version of the NEO software will support the SQLite DB3 wallet format with full functionality. The NEO team anticipates that they will have the new version out in the next few days.
Thank you for your patience.
Please note that:
In most cases you can continue trading if wallet is disabled by using the Markets page (https://bittrex.com/Home/Markets). If there is an issue that would cause trading concerns, we would turn off the market.