Sometime ago I downloaded a ‘Grand Piano’ wav file and began using it frequently since most of my music is piano-heavy. After some time I wanted to try out some new sounds so I downloaded a couple more piano soundfonts and tried them out in LMMS, but there were some that I didn’t like so I deleted them. In the process of deleting these soundfonts I accidentally deleted the ‘Grand Piano’ wav file. I didn’t realize what had happened until a while later when I was listening to some of my older beats and noticed that the piano sound for all of them was missing. At first I was confused as to what was happening but I eventually realized the issue and went to my recycle bin to restore the ‘Grand Piano’ file that I had accidentally deleted. I had hoped that this would solve the issue but unfortunately, that was not the case. This has left me a little distraught because as I mentioned earlier, my music is very piano-heavy. Can anyone provide help or advice on this issue?
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viewtopic.php?f=1&t=4740
-A few rules and useful forum instructions
You mention 'wav' a couple of time, but you mean soundfont -right?I accidentally deleted the soundfonts ‘Grand Piano’
restoring the ‘Grand Piano’ file that I had accidentally deleted. did not solve the issue
Because wave-files are played with AudioFileProcessor
But Soundfonts are played with

Your soundfonts ‘Grand Piano’ should have been reinstated in its old folder, but that only works if you havent made any changes to any folders, and you properly did, when you made the deletions
Was your soundfont ‘Grand Piano’ defined as Default-soundfont?
If so you must insert soundfont ‘Grand Piano’ in the path you have defined in Settings for
Default-soundfont
Edit| Settings |Directories
In this picture its the one in the bottom
Try that first
Let us know the outcome :)