P: Cannot merge panorama after updating to 10.14.6

Rikk: does it seem to you that the common factors are Mac laptops/Mojave/LR 8.4 users? Or did I miss a post?

Just found this and to chime in as well. I to have this issue. I have tried deleting cache, scrubbing Adobe from my Macbook and reinstalling, fresh installing Mojave and Lightoom, trying different cameras and file names, creating a new Lightroom catalog, not allowing GPU acceleration, Changing raw cache size, changing how much ram Adobe can take, changing how Lightroom changes Raw files, Used Raw and JPEG files, Turned off Automatically writing changes to XMPs, turned off develop settings inside metadata, turned off address lookup and face detection (mostly because it says pause and thought it might be trying to do two things at once), tried all kinds of things for creating previews and smart previews (incase it was catching on making the preview for Lightroom). I am sure I have done other things and forgotten them. I spent days so far trying to troubleshoot it. All this didn't seem to make a difference. occasionally, and very randomly, a panorama would finish. But this was very infrequent. Both HDR and Panoramas stall. Yesterday I couldn't get a HDR to finish. 

The only thing that worked was downgrading to High Sierra and an older version of Lightroom using Timemachine. As soon as I reinstalled Mojave though, which I need, and updating Lightroom it stalled again. 

I am running a 2017 Macbook pro 15" 

Lightroom Classic version: 8.4 [ 201908011719-03751b60 ]
License: Creative Cloud
Language setting: en-US
Operating system: Mac OS 10
Version: 10.14.6 [18G87]
Application architecture: x64
Logical processor count: 8
Processor speed: 3.1 GHz
Built-in memory: 16,384.0 MB
Real memory available to Lightroom: 16,384.0 MB
Real memory used by Lightroom: 1,327.7 MB (8.1%)
Virtual memory used by Lightroom: 4,321.7 MB
Memory cache size: 15.3MB
Internal Camera Raw version: 11.4 [ 273 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 489MB / 8191MB (5%)
Camera Raw real memory: 498MB / 16384MB (3%)
Displays: 1) 3360x2100

Graphics Processor Info: 
Metal: AMD Radeon Pro 560

Also had a post up on the forums about it. 
https://forums.adobe.com/message/11202289#11202289

I've the same issue and contact Adobe support, YES, they knew the problems and only told me the support team are working on it. the only thing that I can do now is waiting, such a annoying answer 

Done.

https://www.dropbox.com/s/pdqr79z9fpcs09o/LightroomClassicSamplesFilesPorts.zip?dl=0

Hey Ray, in Activity Monitor, while the Pano is stalled, select Lightroom in the list of processes, then click the little gear icon and choose "Sample". That will generate a process sample showing what Lightroom is doing. Then post it for Adobe. It can help them trace where in the code things are hanging up. Also you can double click Lightroom in Activity Monitor, a window will open, then click on the "open files and ports" tab and there will be a list of every file Lightroom is currently utilizing. Lots of it doesn't matter, but it will also show if there are files open related to caches etc that may be part of the issue.

Rikk, feel free to watch the video link I provided on Page 2 of this thread. I give samples, CPU readings, etc.

all panos.

Hi Rikk, it’s all Pano’s.

Need an additional piece of information. Is this failure on only 360 degree panos or all panos?

I'm out of the office today, but I will follow up with Adobe staff when I get back, don't worry.