Since there was data corruption or at least database inconsistency, it would be good for us to know more about the setup.
Whether it was a release build and the version are helpful.

As far as getting started again, on HDD, I generally use blockchain_import with a blockchain.raw file (available at https://getmonero.org) to bootstrap the database faster than syncing with the daemon:


If you don't have a lot of RAM, you can also lower the batch size, e.g.:


This requires trusting blockchain.raw, unless you run with the default verify mode (--verify on), which is slower, and would be similar to syncing with the daemon if it also did full verification for the entire sync. The daemon by default also trusts some block data to avoid full verification during most of the sync. It's just that the data it's trusting is embedded in itself (from blocks.dat).

In short, if you're on HDD and willing to trust a second file, blockchain.raw, your import will be much faster, possibly even 1 to 2 hours total, depending on your setup.

When the import is done, just run the daemon as normal.

More help on the importer and its options is here:
https://github.com/monero-project/bitmonero/blob/master/src/blockchain_utilities/README.md


Lastly, for HDD users looking for better performance, the experimental performance branch in development is available for testing at exp/performance here:

https://github.com/warptangent/bitmonero/branches

This includes updates that dramatically improve the daemon's interaction with the wallet when dealing with txs that belong to you (e.g. wallet refresh from scratch on a wallet with many txs).

It also includes updates from hyc, the author of LMDB, that improves block storage efficiency.

The latest set of updates I made were pushed yesterday, which deal with transaction storage, notably decreasing the size of the database.

Note that this branch is incompatible with the master branch (and release builds). The two cannot use the same database.

To try it out:


It's compiled with:


All testers should remember it's an experimental branch in development. The improvements also help on SSD, but are especially noticeable for those with slow storage. This is planned to be merged into the master in the future, after further work.

Testing is welcome by all. Remember that the daemon and importer have the --data-dir option, so a separate database can be used for testing.

There could be a couple reasons for the error.

Are you running a released build or one you or someone compiled? What version?

It appears to be on height 0. Does that sound right, or had you previously had a database?

If the former, it would be easiest to start with a fresh database directory and see if that works.

To do so, you could remove the two *.mdb files in your current monero data dir's lmdb/ directory and then start the daemon.

If you want to leave your current database intact for further investigation, you can start the daemon with another data dir:
bitmonerod --data-dir /path/of/your/choice

If you want to follow up, it's better to use the support thread: https://bitcointalk.org/index.php?topic=652305.new

Thank you smooth, MoneroHouse, and donors for the appreciation and support.

Working with the Monero team and community has been enjoyable and engaging, and I look forward to continuing throughout the next year.

Merry Christmas to all of the Monero community.

Note: you might prefer to use --data-dir to specify different directories when running tests, without having to share the same directory and rename files.



Running with --log-level 2 or even 3 would be helpful. That's a lot of output, but it will be saved to bitmonero.log. Its last parts could be pasted to pastebin.

It's too bad the specific exception on crash isn't being shown though. It is on Linux and OS X, and I thought it does on Windows too. If you're using a version you compiled yourself, recompiling with debugging, and running bitmonerod from a MinGW-w64 shell might show the exception upon crash, but I'm not sure.

The logging shown above doesn't include any errors. If you have the error messages available, paste those too.