Seems to me you are overtasking the processor. Even today's remarkable processors will slow down with you send too many tasks their way. Don't try to do too much with too little. Even with the incredible processors we have available today, they are not instantanious. Sometimes we just have to be reasonable about or expectations. So if you want to open 30 images from LR to PS expect some time delay.

I won't even try to address the 29 vs. 30 opening. Don't have a clue. But be reasonable about these machines -- and, yes, they are only machines -- they cannot perform miracles.

Read your original post: You noted that you selected a preset to open in PhotoShop. Please read your original post carefully.

Then you are not expressing your issue in an understandable manner.

"click on preset that I have made to open in Photoshop CS5 as Tiffs, sRGB, 8-bits 300dpi, no compression"

That is a quote from your original post noting that you want to open in Photshop CS5. So what part of opening in Photoshop excactly to I do I not understand?

And then in later posts you talk about only wanting to do tasks in LR. Yet, your original post explicitely notes that you want to open in PS.

You really need to reread your original post and reword it if there is something different you are trying to express.

Do not make assumptions about people you do not know. They may make the same assumptions about you.

Rusty, I think you are entirly wrong and if you do not understand the problem you shouldn't post at all, save us some unnecessary clutter.

OP, I had same issue on LR3 when one photo in a batch would go missing when editing in photoshop. the problem was fixed with the next update.

With the other issue, I think from memory you might have a suppressed warning or somehting that asks about whther you want to render in lr or ps, you might have selected ps and ticked 'do not ask again'? I am paraphrasing my memory so I may not be 100 % correct,but I had this issue too and it was so frustratign that I uninstalled lr and reinstalled, it was then fine, photos rendered in lr as I wanted them.

What kind of preset? An Export preset or an Edit In? Are you sure you are doing precisely the same thing in each program?

Old Plop wrote:

 

I do remember at some point a dialog box asking whether I want ot edit in Ps or Lr, but never got it again and as far as I know I selced Lr.

Then go to the Genertal Tab of your Preferences and click on "Reset all warning dialogs", then try again to see if you get the ACR mis-match message, if you do then try Render Using Lightroom to see if that makes a difference.

Do you still have LR3 available? Try replicating the behaviour using exactly the same originals in LR3.

Trouble is, I can't replicate what I think you've described and you probably won't be satisfied until you've tested it yourself, and "scientifically" - exactly the same  original pictures, same computer, same version of PS/ACR, exactly the same way to go from LR to PS, LR3 vs LR4.

I wonder if you're "simply" seeing one of the slowdowns in LR4. How quickly does export work? Does Develop seem slow?

Killing prefs seems a miracle cure on Mac, but I don't think it's relevant here.

I'd be wary of saying it's your installation. Maybe try reviewing Activity Monitor while running this preset?