AnAnarchist

I've just had the same issue as OP and this solved it for me. I tried the lilypad solution and it wasn't making any difference to the problem but the AHK script works great. I ended up using lilypad for the input plugin anyways so that wasn't a waste of time either

You and me both. Thanks for your and Dos' help. Having some heads to bounce my thoughts off really helped me track down the problem. Hope this helps someone else in the future

No the problem roms were all like follows. So they'd work when loaded from within the emulator but when launchbox passed the rom to the emulator it would fail, somehow reading the html file instead of the bin.

I've solved it!!!! The roms which weren't working had readme.html files in their zips! Alex the kidd had no such file and worked. I deleted the read me from within ecco the dolhins zip and it launches from launchbox flawlessly. It's odd that when the same zip was loaded from within the emulator it dealt with the situation fine but when loaded from launch box it caused an issue.

Why would the exact same rom fail when loaded from within launchbox but work when loaded from within the emulator?

Ohhh I'm on to something now. It's not all my roms that launchbox is failing to load!! Alex Kidd in the Enchanted Castle is launching fine from launchbox wheras ecco the dolpin for example is failing. I wonder if it's got something to do with the Rom name. Checking..

Nope, no dice. I'm just about at my wits end with the genesis haha. Only other emulator that proved to be an equal pain was MAME.

Gave that ago but no difference. I checked the files and they were the same size so i'm pretty sure the emulator isn't corrupt. I've got gens working but can't figure out how to get it launching in fullscreen. It has no command line options, seemingly no option to launch in full screen in the emulator. It has a cfg file with a fullscreen option, but it only seems to work once before reverting to non full screen. Ugh.

Thanks for taking the time to test. I'm on the verge of getting Gens up and running (just looking for the fullscreen command). As for Fusion.. idk I'm stumped. 99% sure the emulator I have is fine. As I said it loads the roms just fine normally. Even when launchbox fails as shown in the image I can right click in the window and choose to launch the same rom from within the emulator and it works. Very odd.

Ugh. I have the same problem with Gens emulator! I don't have any issues with the rest of my emulators..

I can confirm the roms are working and that the emulator loads them fine when selected from within the emulator. It just seems that theres something wrong with the default command line set up for this emulator. When a rom is opened from within launchbox, the emulator opens but it says something odd in the title bar "file was downloaded from <a href='h". It also says checksum incorrect in the bottom right but as I said all the roms work fine when loaded from the emulator. I just get this error when atempting to load from launchbox. Any help would be apreiciated. I've already tried messing about with the command parameters to no avail.