Why does the new Quicktime NOT play my old MOV files?

Question

Hi Folks.
I'm using the lasted updated Yosemite on a 3-year old iMac.
Back in my early iMac days (3 years ago), I imported my camcorder's AVCHD files
into iMove or Final Cut Express and converted them to Quicktime MOV files.
Turns out they were rendered by Apple or Final Cut into MOV files using the
Apple Intermediate codec.  I had no choice over this.
Until I upgraded to Yosemite, I was able to preview any of these movies
very easily in the Finder.  Simply highlight the movie, press the spacebar,
and it opens, in a real-time, real-size screen, with a simple play-pause button
in the progress bar at the bottom.  Never had a problem with any previous
Mac OS.
Now when I click on the file in the finder, instead of a movie preview, I get a
big, silent QT "Mov" icon that just sits there looking silly.
I double click it to open it up in Quicktime, and it attempts to go through this
lengthy conversion process, taking at least as long as the movie is in minutes,
then asking me if I want to save this new "converted" version.
Fortunately, I have an old version of Quicktime 7 on my Mac, and QT 7 opens it
and plays it no problem.  No "conversion" necessary.  No cumbersome and
space-hogging needs to create a "cloned" copy, just so the new, lame version
of Quicktime can play it.
What's up, Apple?  AIC was YOUR codec that YOUR SOFTWARE chose to
transcode into.  Now, your new Quicktime does NOT support this codec?
And your old version does?  And why might THAT be?
Really, this is so elementary.  This is not rocket science.  Just like JPG images
not displaying properly in Mac Mail now.  It begs the question "why" ...?
I mean, for the elementary preview abilities that always made Mac such a
friendly computer ... *uh* ... where is that?
And here we go, wasting hours of time, looking for fixes that should not
have to be "fixed"...
Did I miss something?  Or did you?

Answer 1

Aeclay: here's a couple of ideas.  And an answer to your earlier post.
Basically two options to work with here:
Store the files as native AVCHD files... OR
Convert the files to Quicktime
I keep two archives of my AVCHD recordings, partly for backup, and partly for Sony's ability to archive nicely in it's own native format on it's PC-friendly utility called "PMB".  (came wtih both my NEX and ALPHA cameras).   I have an old PC that I use for my complete archive; Sony's PMB utility works only on PC's and will do a good job both of archiving, providing a thumbnail database, and re-writing your choice to removable media in it's typical Sony hierarchy.
If you've only got Mac's, you can still archive your AVCHD recordings; copy them to folders named or organized to your own spec's.   AVCHD is a high-quality compression format, and they'll take up way less disk space than converted Quicktime MOV files.   You can open and play all AVCHD movies quite easily with VLC player.
The only extra trick to be aware of here is this.  The only reason you would need to preserve the intact "sony" folders (named "AVCHD" / "BMDV" etc) is is you were using Adobe Premiere as a video editor.  Somehow, it needs the hierarchical folder stuff in place to properly index the files.  Not mandatory, but helpful if  you are a Premiere user.  Otherwise, forget the weird "package" folders; just right-click (ctrl-click) on them, choose "view package contents" and MOVE the MTS files out of the Sony hierarchy for permanent storage.  Use VLC player to open and view them.
From that point on,  you have control over how you manage the files and what intermediate or end-user format you convert them to for your own use.
I'm not clear on your other question about the files that add the word "converted" on.  Of course Mac will convert to Quicktime MOV files.  Not sure what codec they're using now, likely H.264.  Anyway, don't bother converting.  It'll take up a lot of time and waste a lot of disk space.
ps. I just found this free utility on the internet.  It's called "MTS CONVERTER". I have not tried it, but it claims to be able to convert all AVCHD files to various useable formats.
Good luck!  (and happy Valentine's Day!)