Can't apply any effects in Premiere Pro v14.9

[#1]

Hi. I am using Premiere Pro v14.9 on an iMac, late 2013, running MacOS High Sierra. All was working well with editing my current sequences until suddenly, today, it won't let me apply any effects whatsoever. Every time I try to drag an effect onto any clip on the timeline, I get the hand / crossed-out circle sign. The clip lines are active and unlocked. I have tried Creative Cloud Clean-up and reinstalling the programme. No luck! It's still doing exactly the same... Am I overlooking something really obvious??

I have an urgent project to complete. Any advice very welcome. Thanks in advance.

[#2]

14.9 requires Mojave or higher.

If I were you I would revert to 14.8 and finish project.

[#3]

Hi Ann. Thanks for getting back to me so quickly. I've been using 14.9 for the past couple of months without any issues - could it be anything else?  Also, I can't see 14.8 available anymore on Creative Cloud! If you have any thoughts about routes I could try, I'd be really grateful.

[#4]

14.8 is still available.

[#5]

thanks so much - this is really helpful - I'll look again!

Heather

[#6]

Hi again Ann. At the risk of showing myself as a real dunce, I've just gone through the process you've pictured above and have now discovered that I'm actually using 14.8 already... 

Sorry for the confusion - and wasting your time.

Does this change anything? It doesn't say that it's not compatible with High Sierra...

Is there another workaround with this new information?

Your knowledge is much appreciated!

Heather

[#7]

Aha, I was wondering how you were able to run 14.9 on High Sierra.

14.8 is compatible with High Sierra.

FAQ: How to reset (trash) preferences.

[#8]

Thank you, Ann - I just tried rebooting Premiere and trashing my preferences - full of hope.

But I'm still getting the same symbol / no luck when I try to apply effects! 😞

I'm sorry this is getting so convoluted.

I'm really at a loss.

If you have any further tips, I'm willing to try (almost) anything!

Thanks again,

Heather