Probably a stupid question, but... how do I prevent the pop-up when adding the first clip to a new t

I went ahead and deleted my preferences trying to troubleshoot a different issue (didn't help, of course). I usually like to do voiceover or sound edits on its own timeline, using raw WAV or AIFF files (no video. Now, when I drop a sound file into the timeline, FCPX complains (see image below). This didn't used to be the case and I can't seem to find the preference for "please just conform to the project properties and quit bugging me". Where is it? I swear there used to be a preference giving me a choice to base it on the properties of the first clip, etc that I could disable. For the life of me I can't seem to find it. It's certainly not in the preferences. I sure hope this isn't something they got rid of in 10.4.

The first line seems odd, the video properties aren’t recognized. Usually appears for non-standard firnats. What are they?

AIFF 16-bit 48Khz sound files. I used to be able to add them into an empty timeline no problems whatsoever and FCPX didn't complain.

I went back to 10.2.3 to see what the behavior is. If I make a new project set to automatic, based on first clip, then I do get a dialog asking to set the specification when I put the audio file in the timeline. If I make a new project with set specifications, 1080p for instance, then there is no dialog when the audio is added.

The behavior’s the same in 10.4.4, only the dialog is the complete project settings sheet. In the older version the drop down sheet was just the resolution and frame rate.

I swear in older versions there was a box you could tick that was "Set project properties based on first clip" or some such thing that seems to have gone away for some bizarre reason.

May have been. There was in legacy FCP, but that’s what the default automatic setting in the new project dialog does.

I have always started many projects with VO audio file delivered to me at the TV station, for years, and being asked for video format when Timeline is set to auto has always been the behavior, since 10.0.0.

That's weird, because it's always just obeyed my project settings. I'm sure I have something configured wrong somewhere, I just can't find where.

If you specify project settings, it won't ask. If you leave it to the auto-configure setting, it will ask. I've never seen it do otherwise.

The select project based on first clip has always been and still is there. Click the automatic settings in the project creation dialogue to get back to it if yours is custom.

It's working as expected for me now. Not sure what I was doing wrong before but I hope I don't do it again!