UPDATE (21st May, 10:49 GMT): A Chrome product manager has provided more information on the reasons behind the outage. More details here.

UPDATE (20th May, 9:30 GMT): Co-founder Steve Dakh says Google has now responded and reinstated KryptoKit's account, meaning users should now be able to access their wallets again. Still no detailed reason has been given for the removals.

KryptoKit, the bitcoin wallet and encrypted messaging extension for Chrome browsers, was today mysteriously auto-removing itself from users' computers – along with easy access to the bitcoins they kept there.

Developers from the KryptoKit project were frantically working to find the reason and a solution, and it was not known for sure whether all users would be able to regain access to their funds. The extension stores a private key seed locally on each machine, though some level of technical knowledge is required to find it.

Some users reported success with shutting down Chrome, disconnecting from the Internet and then restarting it. From there, either before or after reconnecting to the Internet, the reappeared extension may be able to create a backup file or export the 'brainwallet' private key generator.

Around 6:00am GMT users began to flood twitter and reddit with messages saying a popup dialog box had informed them the extension had automatically removed itself from Chrome. Two buttons on the dialog said 'OK' and 'Details' – the latter of which took them to Google's Chrome web store, from where they found KryptoKit had also disappeared.

my #KryptoKit #bitcoin wallet was just automatically removed from the chrome browser. wtf? @KryptoKit

– Assaf Shomer (@BeatTorrent) 20th May 2014

Six month-old Kryptokit had support from some prominent members of the bitcoin community and had been well received by users until today. It even had a partnership with BitPay to include a 'two-click' solution for easy payment to bitcoin-accepting merchants.

Within the hour, project backer Vitalik Buterin posted on reddit that Google had removed the extension "for unspecified TOS [terms of service] violations", and that KryptoKit co-founder Steve Dakh had "been stonewalled" when asking Google for a clarification.

"If you made a backup, then you should have your brainwallet seed in the backup file, which you can import into blockchain.info or simply pass through sha256 to get your private key out," Buterin wrote, adding:

He then posted some command line directions for Windows and Linux users to help locate the brainwallet – a 50-character string in a directory containing Chrome's user data. This can then be imported into blockchain.info or converted to a private key.

Whatever the reason, if Google is responsible for the removal it seems to be an aggressive move. Users were presented with no choice as to whether or not to remove software they had installed on their personal machines; software that also held access to their funds. Such a sudden removal would usually be reserved for dangerous malware.

Unlike fellow tech giant Apple, Google has so far not shown any opposition to bitcoin or its use on devices running its software. There have been no reports of other bitcoin wallets, including those installed on Android-powered mobile devices, being removed.

KryptoKit

launched in December 2013, promising a simple and easy accessible wallet with no logins and passwords, that could also send encrypted messages. One useful feature was its ability to identify bitcoin addresses on a webpage, allowing a user to select from a drop-down menu instead of copy-pasting or scanning a QR code.

The extension is the product of developers associated with the Bitcoin Alliance of Canada, including co-founders Dakh and Anthony di Iorio. Launched in December 2013, a month later it received backing from high-profile bitcoin figures Buterin, Roger Ver and Erik Voorhees.

CoinDesk will continue to monitor this developing story.

Image via Kamira / Shutterstock