As long as you have your wallet DAT file backed up somewhere you aren't formatting it should be fine, I made a thread on this issue because I'm going to be doing a format tomorrow as well and wanted to double check things.
https://bitcointalksearch.org/topic/m.9696614
Topic: I did it! (Read 1757 times)
I had a format C: recently so I need to download it again, it's a nightmare but this time I saved the entire Bitcoin folder with the blockchain and everything. I hope that when i try to use the already downloaded blockchain I don't get it corrupted as it has happened everytime I tried to use my backup downloaded blockchain. I hate this thing but im paranoid about using anything that isnt the Bitcoin Core.
Happy you...we will have many discussions on btc forum.... 
It takes three days for me, but now its running. :-)
Why you do it?
you will need to update every day, and that will take some time.
you will need to update every day, and that will take some time.
Because the Bitcoin-Qt wallet is the most secure. Eventually they will have to implement
a feature like in the Electrum wallet where download of the entire chain isn't necessary.
Wow congrats
I finally finished downloading the Blockchain! on my iMac!
It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
What was the size? My download speed is 2 mbps, so how much time it may take?It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
Canny wait till ye huff tae dae it again.. n huff, n puff.. dont le me blow your house down, just shtoom..
I finally finished downloading the Blockchain! on my iMac!
It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
What was the size? My download speed is 2 mbps, so how much time it may take? It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
What is the size of the blockchain right now?
322791 Blocks
Bitcoin wallet update today 25.4 Gb size on HDD
Why you do it?
you will need to update every day, and that will take some time.
you will need to update every day, and that will take some time.
What is the size of the blockchain right now?
322791 Blocks
I finally finished downloading the Blockchain! on my iMac!
It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
WOW that was quite fast!
It took me almost a whole week.
Could it have been my computer's specs?: Processor 3.5 GHz Intel Core i7
Memory 32 GB 1600 MHz DDR3
Graphics NVIDIA GeForce GTX 780M 4096 MB
Software OS X 10.9.5
Now port forward 8333 to run a full node! 
I want to but I'm not trech savvy enough to do this.
I literally need a step-by-step guide.
I could tell a friend to create a youtube video for this. I see that no one has created a detailed how-to guide yet. It's quite different for each router though.
Yes that would great! I really want to support the network as much as I can. I can take a picture of my router and post on this thread.
I finally finished downloading the Blockchain! on my iMac!
It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
It took an entire day!
That's all I really wanted to say.
Bitcoin rocks!
WOW that was quite fast!
It took me almost a whole week.
Now port forward 8333 to run a full node!
I want to but I'm not trech savvy enough to do this.
I literally need a step-by-step guide.
I could tell a friend to create a youtube video for this. I see that no one has created a detailed how-to guide yet. It's quite different for each router though.
Now port forward 8333 to run a full node!
I want to but I'm not trech savvy enough to do this.
I literally need a step-by-step guide.
when I downloaded took several days because I can't let the thing download all the day.
Good for you it was quick
Good for you it was quick
Now port forward 8333 to run a full node!
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