Bitcoin Forum

So I've recently being playing Dragon Age Inquisition ( Bear with me it does get back to Bitcoin ) and in order to get round those stupid operation durations in the war table you can change the date forward one day and back again because those morons at EA decided that you should have to wait for 2 hours in real time for an operation to complete and give you a shitty item at the end of it. As it turns out one time I forgot to switch back the day I was on and even though it was 04/03/2015 at the time of a transaction to my wallet the wallet somehow believed it was 05/03/2015 and despite me fixing the date, it still believes the transaction happened today despite it actually happening yesterday, while this isn't a huge deal it makes me wonder about potential problems it might cause.

I could be just being paranoid obviously so feel free to tell me if I am but I'm just surprised at how many programs rather than having their own internal calender are simply linking themselves to the windows one, for the record I'm on Windows 7 Ultimate, I suspect though you could even replicate this on mac/linux if Bitcoin-QT is setup in the way I suspect, I've just never ran into this sort of thing before because the calender is never really something you think about much.

Now I've thought about it more obviously the blockchain would still record the proper date and time wouldn't it? However I was wondering if maybe you could switch up somebody's calender to make it seem like the transaction happened at a different date etc. so someone less experienced would freak out over it.

AFAIK, it uses local time to read the blockchain, but to send transactions it saves the time, not local, when it got relayed.
Not 100% sure, its been months I really played around with those things.

Right, so it's not a huge deal then, I just found it interesting and wondered if anyone else had messed with this.

Operating systems adjust the real-time clock on the motherboard when their clocks are adjusted.  When the computer is off, only the RTC is keeping time.  IOW, even if an application tried to keep time separately, it couldn't do so when the computer was off.  For an application to have a different time, it would have to connect to a time server.  Time servers are not decentralized, so it wouldn't make a lot of sense for a decentralized currency wallet to rely on one.  If you don't run Bitcoin-QT for a month and have some receipts, I believe they will show up as received the next time you run the wallet as the blocks are downloaded.  This would imply that the times in wallet softwares are only there for reference.  It is important that your system time is correct if you're mining because some level of consensus is required on the times in the blocks, but even the times on blocks is not incredibly accurate, because it is sent by the miners.  For transactions, though, I don't believe a separate time is sent or stored (outside of nlocktime or some other feature that isn't relevant here).

This! Transactions have no timestamp on the blockchain, but only the block they are stored in. Thus your changed local time would only confuse yourself not someone else.