BitcoinTalk

Before the node finishes IBD, you will not be able to see a new transaction related to your account until the client has caught up to the block containing that transaction.

If you are trying to set up a new node following the instructions below, you will go through the IBD process at the first run, and it may take a considerable amount of time since a new node has to download the entire block chain (which is roughly 195 gigabytes now).

During the download, there could be a high usage for the network and CPU (since the node has to verify the blocks downloaded), and the client will take up an increasing amount of storage space (reduce storage provides more details on reducing storage).

This will happen when a node is far behind the tip of the best block chain. In the process of IBD, a node does not accept incoming transactions nor request mempool transactions.

So your wallet may not count new payments/spendings into the balance.

If you are using Bitcoin Core GUI, you can monitor the progress of IBD in the status bar (left bottom corner).

Initial block download refers to the process where nodes synchronize themselves to the network by downloading blocks that are new to them.

Attack target: Bitcoin Core powers the Bitcoin peer-to-peer network, so people who want to disrupt the network may attack Bitcoin Core users in ways that will affect other things you do with your computer, such as an attack that limits your available download bandwidth.

Anti-virus: Several people have placed parts of known computer viruses in the Bitcoin block chain. This block chain data can’t infect your computer, but some anti-virus programs quarantine the data anyway, making it more difficult to run Bitcoin Core. This problem mostly affects computers running Wi...

We advise that you check whether your Internet connection is subjected to such limitations and monitor your bandwidth use so that you can stop Bitcoin Core before you reach your upload limit.

Worse, some providers may terminate your connection without warning because of overuse.