Hey @Zomer_Yevgeny, sorry about this! Good news: nothing’s lost. A stalled rebuild like this times out on its own and leaves your existing computer (bots, files, and logins) intact, so it should come back on the previous version.
If the “Transferring your data 43%” screen is still up, fully quit Grok Bot (exit it completely, not just close the window) and reopen it. Please don’t press Reset or Update again while a rebuild is running, since extra attempts get refused and slow it down.