Can't write a Jingle now - Since July 18, 2023

@Siluial   Hi!  Sorry you're having trouble with the musician!  I have a musician sim also and just tested this.  The option to Write Jingle showed every time for me.  Have you tried traveling to another lot?  Sometimes this will clear glitches that may be happening in the background.  You might also try exiting the game and running a repair.  If you do that, I recommend allowing the repair to run for all packs, even if you get a prompt that the game is ready to play.

Also, there is an open bug report about the issue of losing progress for writing songs (and books and lyrics) here.

https://answers.ea.com/t5/Bug-Reports/OPEN-Write-Song-Book-Lyrics-Loses-Progress/m-p/11684183

Please click "me too" on the first post and feel free to share any comments that you feel are relevant.

Yes, I've traveled to other lots.  

Yes, I did a proper repair - I always wait for it to run fully.

I will check out the link. 

Thanks!

UPDATE: Apparently, to write a jingle, one must be in the MUSICIAN career, not just be a musically inclined Sim. 

So, I suppose this part is solved - But not sure how to close it. 

Still have issues with books/writing songs/lyrics where quitting the game starts my progress over... 

@Siluial    That is really strange.  When you traveled to other lots, did you try clicking instruments like the ones on the Solar Flare lot in Oasis Springs or just your own instruments in inventory?  Have you tried buying new instruments?

I wonder if you might try saving the musician sim and loading them into a new save to see if you get the option there.

Edit:  OOPS!  I didn't see your post until after I posted this.  We must have been posting at the same time. :-/

Edit 2:  I suggest marking your post about needing to be in the musician career as the solution so other players will know.  I'm glad you were able to figure that out!

I don't have issues traveling... 

Let me explain.

I want to play Sims today, say. So I login to my EA account, select Sims 4 and play. It loads, I pick my most recent family (could be one I've saved in the past, doesn't seem to matter). I decide I'm going to write a song today - my Sim has no other obligations and has the time. If I keep her (or him) doing nothing but writing the song, the song is finished by the end of the day and I can interact with it - license the lyrics, song, etc, or send the book out for publication, you get the idea.

If I decide my sim needs to eat, go potty, go be social, go to the festival, go on vacation, etc... I can do all those things and come back to my lot and the progress on my book or song is the same as when I left. It's the same game. 

However, let's say I don't have time or the desire to sit at my computer all day. So I start my sim writing her song (or book) and after awhile, my son needs me or I have to run an errand. So I select: esc, save. Then esc, save and quit. The game closes, I shut my computer off and go do Real Life Things (tm) ... A couple hours later, I return, have some time, bring my game back up, login, yadda yadda. I'm back in the same lot, same family, and see my Sim has stopped writing the song (or book) so I start them again. It's as if they're starting from scratch - DESPITE the item in my inventory (in the case of lyrics/songs) or having the option to resume writing (in the case of the book).  In this case, I've left the game. Not the world, the GAME. 

Make sense? 

Updated! Must be in MUSICIAN CAREER to Write JINGLES

@Siluial   I was actually suggesting that you mark your own post as the solution where you mentioned needing to be in the career to write a jingle. :-)   I think you should still be able to do that if you want.  In the meantime, I've edited my post so that it's clear to everyone.  Thanks so much for providing the updates!