If running the client executable does nothing or gives you an odd error before dumping out, here are some common fixes to try:

1. Look for a 'crash.log' in your 'db' directory or user desktop. Failing that, is there a 'client - [date].log' file? Does it have an error in it? If there is something, please send it in to me, hydrus_dev (see contact.html in the help directory for my contact details).

2. Some anti-virus program updates falsely detect that one of the dlls or other files in the client is bad and quietly quarantine them. Please check your anti-virus logs or compare your install directory with the 'extract only' release archive to see if there are missing files. Avast has done this several times. Instances of this are useful to know about as several users usually get hit by the same thing at the same time. Please feel free to also start a conversation if you just want to double-check it is a false-positive after all.

3. Extract a fresh 'extract only' client to your desktop and try running it. If an empty and new client boots but your existing client doesn't, that suggests there is either a problem with your database or a conflict with some older dlls from a previous install. A database problem will typically be reported in one of the log files, so you might like to try making a 'clean' install.

Making a clean install:

Delete everything in your install directory except the 'db' directory. The 'db' directory is where your settings and files are kept, so leave it alone! Then just reinstall or reextract the latest release.

4. Check your permissions and hard drive health. For instance, sometimes when a hard drive has a fault, Windows sets it to 'dirty' mode, which causes all sorts of problems. Linux and OS X have presented their own permissions headaches. A default client works in 'portable' mode and needs read and write access to its 'db' folder.

5. Going forward, please consider making backups before you update the software. If a future update has a serious problem, it is then easy to rollback to the working version while we figure out a fix!