Disappearance of several orchestral parts namely the trumpet
Throughout my writing of my first complete waltz in my first jazz suite, "Aurora", I did not notice any abnormalities and thus without checking had gone to bed. Upon the time where I woke up did I realize that the entire solo trumpet part disappeared, leaving virtually empty staves except for one single orchestra strike, which was the only time where the trumpet played. Could this be a possible error in the software, or a negligent mistake by pressing the wrong keys on my computer?
I also have other information to provide; the trumpet was not marked "soloist", rather assuming its own position in the brass band in customized orchestral ordering; the only thing denoting it as such was text which I had placed above the staff which pertains to the trumpet.
Furthermore, I tried reverting to backup variants and they all had the same issue; the Bb trumpet part was gone, and being a jazz suite the trumpet is a leading instrument with equal trisection of melody between it, the woods, and saxophones. This issue is quite distressing considering that my creativity at the moment is running low and as such I cannot rewrite the trumpet part up to standard; and furthermore there is also risk that some other vital parts of the orchestra will be deleted without my knowledge.
Could someone help me understand the nature of the problem? Any assistance is greatly appreciated.