Do not panic on a recording session when unexpected problems emerge, a quick advice.
Dear reader, I have had the fortune and joy of conducting my own music on many occasions at professional and iconic recording studios like East West Studios in Hollywood or The Village, which are two of the most well known studios in Los Angeles. It is on these recordings that unexpected problems arise and are nothing uncommon, so, in hope that you learn something useful for your future recording session, allow me to share with you three of the most memorable situations that fellow composers and myself experienced on different recording sessions and how we fix them on the spot so the session went on smoothly and saved the day.
Problem #1 Wrong key
At East West Studios, one of my fellow composers had his clarinet part in another tonality than the intended (C instead of Bb), luckily for him someone brought a laptop with his notation program and she (my fellow composer) had the files she needed to edit, so we (other fellow composers and myself) arranged her recording time for the very last. At the end, she managed to transpose the clarinet part to the correct key just in time. The lesson I learned was that, if possible, and as a security practice one may bring their notation software to the session, just in case.
Problem #2 A mistake on music parts
I made a mistake on one bar of every music part I printed, thankfully I noticed this when I was hanging out at the lounge of the studio before the session even formerly started, so I could point to the musicians where was the issue, I was very thankful that I saw the issue while I was on the studio waiting for the session. My suggestion would be arrive early to the session because it was on this time where I could notice my fault plus it is a good practice to follow.
Problem #3 An additional player and a missing player
Once, I asked the instrument list for an upcoming recording session which I was a part of, I got a misleading message with a typos and got confused (I should have double check), instead of 2 Cellos, I understood 1 Cello, plus I thought there was going to be a clarinet player which was not the case. I noticed the problem on arrival to the session so I quickly took out a copy of my Cello part and gave it to the second Cello player. For the Clarinet part I asked the trumpet player if he could play that part but with a mute (to approximate more to a clarinet sound).He said yes. It worked, as the range was doable, and the clarinet and trumpet parts were not playing at the same time. I remember thinking, "I got to do something and fix it quickly" which I did but it was not funny... specially at the moment but I got lucky, it could have turned out worst.
Anyways, I hope this is somehow useful to at least one person and that in your future recordings you stay more aware and alert of these problems than what we were back then when we face them for the first time.