Several years ago, without really understanding the mechanics relating to bitcoin, I believe I might have managed a bit of mining. The "Bitcoin-wallet" and other files, including my wallet.dat file have been sitting on an old PC that I only found during a recent move! So am now playing catch-up and have a few questions (noting that I have copied over the relevant files and wallet.dat to external drives).
When I first tried to open the wallet there was an error/warning about corruption but asked if I wanted to proceed. I did. After updating the time and date of my old PC to today's date/time, the wallet started to work. That is while my wallet indicated that it is "out of sync" and showed a balance of zero, it did start syncing with the network. It is now telling me that it is over 10% done and that are "XYZ" blocks remaining. What does this mean? And will my wallet be updated only when the synchronization is complete?
Also, at towards the top of the wallet is there is a message "alert key comprised, upgrade required"
Thanks for your patience.