There is no need to have to export your keys when upgrading across Bitcoin Core versions. All of the wallets are compatible.

Again, the wallet is not version 4.8.3. Look at Help > About Bitcoin Core and it will tell you what version of Bitcoin Core you are using. The Qt version doesn't matter.

You get your private keys using dumpprivkey. I described how to do that here: https://bitcointalk.org/index.php?topic=1488610.msg15015386#msg15015386. If you are getting an error, then please tell us what error you are getting.

If that computer is off most of the time, then any desktop wallet would be safe. Electrum is a good choice and when you need to use the wallet, it will be very quick to start and be synced.

Nope, but it may be a good idea to hold onto your wallet.dat file anyways.

No, it does not download the blockchain. It is called an SPV wallet. Basically it means that it lets someone else download the blockchain and then it requests its data from that person. There is a little bit of trust involved as you need to trust that the server providing you the data is not malicious and will not give you bad data. This makes it only slightly less secure than a full node.

Right, that makes sense. Bitcoin Core eats up a ton of bandwidth anyways from normal operation.

Yes. It will pick up from where it left off.

Having to continuously reindex is usually indicative of failing hardware. I suggest that you run some diagnostics on your hard drive to see if something is wrong.

If nothing is wrong, the best solution is to probably start from scratch. This means that you delete all of the blocks and databases and allow Bitcoin Core to fully sync from the beginning.

You can enable pruning by using the -prune option in the startup command. This will still have to download the entire blockchain but most of it will be deleted thus saving space.

Yes.

No, but if you want it to happen quickly, you should probably export your private keys from Bitcoin Core and sweep them into Electrum.

Can you provide the FULL debug.log file?

Qt 4.8.3 is NOT A VERSION OF BITCOIN CORE. That is the version of the GUI framework (Qt) that is used by Bitcoin Core. 4.8.3 hasn't been used by Bitcoin Core in a while, so you are probably using 0.9.x or earlier.

You are using old software. I recommend that you first upgrade to the latest software, Bitcoin Core 0.12.1. Let that run and see if that has any issues.

Can you provide the debug.log file?

Qt 4.8.3 is NOT A VERSION OF BITCOIN. That is the version of the GUI framework (Qt) of your version of Bitcoin Core. 4.8.3 hasn't been used in some time, so you are probably using Bitcoin Core 0.9.x or earlier.

The same process can be used. It hasn't changed in a long time.

That is not mining. That is cloud mining, which is usually a scam. Actual mining is using computers (ASICs really) to hash block headers until the resulting hash is below a certain target. Actual mining is not very profitable without investing a lot of money into hardware.

Thanks!

That's not going to help with the software continuously crashing.

OP, please post the debug.log file. It should be in the same place that you found the wallet.dat file.

He's also posting the same message in threads now, not just creating a new topic.

Please post the debug.log file, your crash log means nothing to us as that is generated by the OS, not Bitcoin Core.

Your Bitcoin is safe so long as you do not delete your wallet.dat file. It doesn't matter whether your wallet is synced as once the transaction is in the blockchain, the wallet will be able to find it when it does sync up.

You could enable pruning which can save space. It will still need to download the entire blockchain but most of it will be deleted after it has been downloaded and verified.

The setttings for that are stored in the registry (or whatever the mac equivalent is) and once it is in there, Bitcoin Core will always know that it is no longer the first session. The solution is to use the -datadir option. I'm not quite sure how to do this in a Mac, but what you need to do is find where the startup command is (probably in a shortcut) and add the following to the end of the command:
where <path to datadir> is the path to the new data directory. Make sure there is a space between this option and whatever is already there for the command.

That's a whole other problem and we will need to see the debug.log file to figure that out.

First, you must find the wallet.dat file and back it up to a safe location. That file contains your private keys that you need to spend the Bitcoin. You could export the private keys and import them to Electrum, but my solution above with the datadir should fix your problem.

Download the code for bitaddress.org from https://github.com/pointbiz/bitaddress.org. Take that to an offline machine and open up the bitaddress.org.html page. It will be just like the website and you can create a paper wallet from there.

You'll have to dig through the source code: https://github.com/bitcoin/bitcoin

Here are pastebins of the logs. He emailed the logs to me, which are also already posted.

Cpp log: http://pastebin.com/3eKRaWxy
log: http://pastebin.com/fqvUJM0k

What I see in these is that it looks like there is already an instance of Armory running when you last ran it. It should have warned you with a message box that there was more than one instance of Armory running and then exited the program. If it didn't, then something is wrong.

Your log files will be too long to post. Just put them into a pastebin and post the link to that pastebin.

Check out bitcoinj: https://bitcoinj.github.io/ if you want to use java. You will need to know, at a bare minimum, how to use methods, handle exceptions, and use multiple classes and objects in order to do anything. If you don't know any of those, then you should learn.

Again, I highly advise that you find some course in whatever programming language you want to learn and learn that language until you are proficient and comfortable using it BEFORE you attempt to do any sort of large project. If you want a place to start, I suggest checking out wikiversity.

Yes, you have to learn, but do not jump straight into attempting to program a large project. However, you should learn the language(s) that you will need to create that app. If you want a desktop app, try learning python, java, or c++. If the app is windows only, then you will want to learn C#. If you want a web app, then javascript is usually the way to go. For mobile, Java is for Android and objective C for iOS. These are the most popular languages.

If you don't know how to program, then it is probably a bad idea to attempt to create an app without first learning the basics, especially when you are dealing with an app that could potentially risk people's money.

What you want to do is import the private key to Electrum.

To do so, first export it from Bitcoin Core by going to Help > Debug Window > Console. In the textbox at the bottom, type
where <address> is the Bitcoin address that you want the private key of. The output of that command should be in black text at begin with 5, K, or L. If it does, then the export was successful and you now have the private key. DO NOT SHARE THE PRIVATE KEY WITH ANYONE. Do this for all of your private keys and record them in a secure place.

Then go to Electrum. Create a new wallet from File > New/Restore. Name it and then choose the option to "Restore a wallet or import keys". Click Next and in the large text box in the next window, enter your private keys, one on each line. Then follow the remainder of the wizard to import the private keys to a new wallet.