AVCHD video from Canon C100 stuttering in FCPX 10.4

Here's a technical question for Tom maybe... anyone really! Would it be possible to run both 10.3.4 and 10.4 at the same time on the same machine? Maybe 10.3 under one user account/login on say an iMac, and 10.4 under a different user account/login?

If that's possible, then maybe at least I'd still be able to use all of my computers for importing and editing the same projects across the board until (hopefully) Apple fixes this problem.

Oh well... figured it was worth asking anyway. At least I hung onto 10.3 on one of my machines for importing. It would be nice if Apple would at least make 10.3 available as a download to other subscribers who weren't as lucky while they sort this out.

I have shelled out the $70 AUD for EditReady which solves the problem to an extent. It adds another step to my workflow and adds about 2-4 hours to each cut but at this stage it seems there is nothing else to do other than leave FCP X completely and go back to Adobe.
Apple have shown nothing but total contempt to their users on this matter with no feedback at all let alone a fix.
A simple, "we acknowledge the issue and are working on a solution" would go a long way but instead a wall of silence.

You got some communication from Apple related to this issue?! Over the years, I've probably submitted a dozen Feedback tickets via that link you posted. I've never once gotten a response from Apple about any of my issues. You getting a response is like finding the holy grail for us pro users regarding communication from Apple.

What did they tell you about the issue? Are they working on it? Do they hope to resolve this issue with AVCHD footage (AVCHD/interlaced footage is the common denominator for all of us... I'm filming with Canon XA10's.)?

I called in a few times too, offered up lots of documentation to help narrow the issue. It took some escalation up the chain, you have to be nice and persistent.

My problem with the C300 and Canon XF codec was addressed in the 10.4.1 update, but the fix actually made things worse. I'm still hoping for a fix that takes things back to pre 10.4, but who knows how far off it is. Seems like lots of issues for Canon gear right now.

It's really hard to believe that some things that have always worked perfectly since the advent of FCP X can suddenly stop working properly after simple updates. And it's even harder to believe that Apple won't make the version that did work for us well, 10.3.4, available again for download until said issues are resolved.

It would seem to have been put into the too hard basket. I have now bought EditReady which is allowing me to continuing using FCP X but it's really annoying.
I wonder if Apple will give me a refund on the $70AUD it cost me so their software works again after their "upgrade"

I received an email from the Apple Pro Apps team from Apple on Friday. They instructed me to update to 10.13.5 and asked if I could import some AVCHD and see if that resolved the problem for me, that they believed the 10.13.5 updated would resolve the issue.

I updated my MacBook Pro to 10.13.5 and tried an import with no success.

Today, I wiped my MacBook Pro and did a clean install of 10.13.5 from a bootable disk I created. Then I installed FCP from the App Store. After another attempt at an import, I'm still having the same issue.

It's not as prevalent or common in the footage as before. I found three instances of pixellation at the top of the screen in a clip just over an hour long, where before, maybe it was a couple dozen. But the problem still exists (using Canon XA10's that film to AVCHD).

So, for me at least, 10.13.5 is not a fix. But I'm encouraged to finally have this problem officially recognized from the Apple team. That tells me they're determined to fix this issue, for which, I'm appreciative.

That's what I feared. Sometime in the next week I'll upgrade myself and see how the problem has improved or not.But yes, it's good to know that at last somebody at Apple is acknowledging that the problem exists.

I'd like to follow up one more time. I'd like to make clear, THIS MAY BE A FIX FOR MOST OF YOU! I've done more tests on some other footage and it only appears that the issue only affects clips longer than an hour long. I can't find any artifacts in shorter clips. And, oddly, in two of my tests on clips over an hour long, the artifacts have only appeared around the 40 minute mark. In both tests I couldn't find any artifacts in any other part of the clips. So, if any of you never film anything over an hour long, you may be in luck with his latest OS update.

For me on Panasonic AVCHD, same problem.

I downgraded OS to 10.12.6

There I can work with FCP X 10.4 without hiccups.

Did you send feedback?

From the Final Cut Pro menu.

Yeah I'm having that red issue as well. Very annoying.

I'm also having this problem. Seems to be random in terms of when it happens.