Damn, I've a Similar Situation Happen today. I was working on a Project, Hit the Save Button cuz I had to leave. After it Saved Exited out of LMMS then Hit the Physical Power Button on my Computer. Came back tried to load up the previous file I saved. It said " The File <File Name> seems to con...
I Already Solved This Exact Problem.
Use the VST Tuner and it will tell you what root note your 808 plays. Tunes 808s PERFECTLY EVERYTIME!

https://lmms.io/forum/viewtopic.php?t=30168
oh silly me from the past hello, I solved the solution for now. Just use a VST Plugin called tuner. It will tell you what is the root note of the sample easy peasy. Maybe LMMS new update can come with Tuner Pre-Installed or make their version. I don know buy hey problem solved. Also use that wine sh...
Every single sound has a root note but not every audio file/sample is recorded at that root note. Why does this matter? well because when you start making music, everything is not at the right pitch or note. So when using an audio sample for example an 808/bass or a brass hit sample, it makes it har...