It is not dependent on the file. Even in a file with no comments, the Comments panel takes 30 seconds to open.

As stated numerously, it doesn’t depend on the file.
But if you insist, here is a file: https://adobe.ly/2JNq6VT

It takes me 7.5 seconds to open the comment-pane.
Im on Version 2018.011.20040 and Build 18.11.20040.280397

As I've said before on this tread (approx 6 months ago), this is related to unpublished books which are confidential and which I therefore can't share. Sorry

Thanks everyone for reaching out to us. We tried to reproduce the issue at our end but were unable to do so.
Please provide the sample files on which the issue is reproducible. It will be of great help.

I have this issue also;
1. Acrobat Version 2018.011.20040
2. macOS 10.12.6
3. Time to display comments panel: 30 secs (Current file has 33 comments)

However this is independent of the amount of comments contained in a PDF as it still takes 30 secs even when the PDF on my mac contains no comments.

Will this ever be fixed??? This is killing us. I should have known what moving to a subscription model would mean. No service and a steady decline in quality. I hope we can find an alternative to Acrobat soon. It just doesn't work anymore.

The status button says “Need Info”. What kind of info do you need?

E.g. MBP 13" mid-2012, i7, 2.9 GHz, 16 GB RAM, macOS 10.13.4, Acrobat build 18.11.20038.267465

PDFs exported from InDesign 13.1 on Mac, commented in Acrobat Pro DC on Windows (most recent version) – time to open comments on above Mac:
2.9 MB, 160 pages, 8 comments – 23 s
4.6 MB, 264 pages, 43 comments – 6 s
2.1 MB, 112 pages, 68 comments – 15 s
2.4 MB, 92 pages, 30 comments – 6 s

I just don’t get the pattern …

It takes over 30 seconds to open the comment panel, regardless of the number of comments or the size of the document. This has been an issue for a long time. A fresh install doesn't seem to help.

Clicking on the comments list (only 4 in this document) is a 10-15 second delay, plus 5 seconds of beach ball and then I see the comments. This is such a slow down in production and very annoying.

Acrobat Pro DC, 2015 iMac, 10.11

I have been aggravated by this issue for at least a year. I need to open multiple documents and view comments and each time it is an agony of waiting. I tried clean installing Acrobat to no avail. I then found some comments8 (I don’t remember if it was here or elsewhere) and they were correct. If you log out of your account and then into a guest account and open Acrobat, the comments open immediately. Go back to your own account and slow as molasses again. According to the commenter, this is an issue related to the user’s identity info on the Mac. I don’t have the slightest idea where I would even find that to change it. But the fact that comments open immediately in the same docs on a PC seems to support this theory.

Little update on my situation. Got a brand new install on a new Mac Pro. Just Adobe CC installed. My previous computer went through several versions of Adobe products. Now everything runs normally as far as comments loading goes. If that can help troubleshooting the issue.

I would like to add my experience. The comments list loads fine, but there is a serious drag when scrolling through and marking it. It adds to the time needed to make edits and is very frustrating. I have noticed that my Adobe Bridge has a similar drag when scrolling through photos.

Adobe Acrobat Pro 2017
Macbook Pro, Sierra 10.12.6

Adobe Acrobat Pro DC, fresh install 2018, cannot get the comment in the pdf to select (will not open when I double click on it) and since it will not select, it doesn't sync up with the comments panel, and bring that page's comment within view, it lags way behind. 711 pg pdf, 971 comments, 19.89 MB. XI worked fine. PDF is saved to desktop, location is trusted. Worked fine yesterday on XI Pro.

Acrobat 2017 Standard perpetual - 900 comments. Loads extremely slow on a Dell E6540 with 8 GB of RAM and with at least 4-5 other applications opened that are required for the user's job.

Works perfect with Acrobat XI Standard, mainly because the Comments tool does not keep re-loading like it does with the 2017 version. We have applied the latest updates to Acrobat 2017 Std perpet., but does not fix the issue. Thank you.

I am having extremely long load times. The worst part is if I am working off the network. Once I log into my Companies network, every file I open afterward loads slow. Even if I am opening from my email or desktop. The files i am opening are usually 5MB or smaller and only 1 or 2 pages.

MacBook Air 13inch
2 Ghz Intel Core i7
Memory 8Gig 1600 MHz DDR3
Graphics Intel HD Graphics 4000 1536 MB
Mac OS 10.11.6

It's currently unusable for me.

Admittedly it's a big document (1750 pages, ~1360 comments), but it hangs for 10s of minutes. High Sierra, latest acrobat DC, MacBook Pro 13 with touch bar. Lots of memory and SSD.

Yes, there is a lag, but for me it's 2 seconds on my laptop with High Sierra. I haven't checked my old or new iMacs, as I am not home.
MacBook Pro (Retina, 13-inch, Early 2015)
2.9 GHz Intel Core i5
16 GB 1867 MHz DDR3
Intel Iris Graphics 6100 1536 MB

For me, it takes 30 seconds to open the comment panel, even if a document has no comments. Doesn't matter which document or the size of the document. Has been happening for a long time and the lag does seem to be getting longer.

Mac OS 10.12.6
Acrobat 2018.009.20050

Ah! The age of the installation makes sense! The only time my comments pane was snappy was when I was recording an Acrobat course at Lynda. The comments pane opened instantaneously! I thought it was perhaps because of their crazy fast computer. But now that I think bout it, that Acrobat installation was probably done just a couple of days before I used it.

As all others have said. Open any PDF document that contains comments. Click the 'Comments' button to open up the pane. Wait. Everyone in our office has experienced this issue since the beginning of Acrobat DC. On newer SSD Macs it's more bearable, about 3-4 seconds wait. On our older Macs with spinning hard drives it takes as long as 30 seconds for the comments panel to open. For some reason the delay seems to get longer and longer as the installation of Acrobat ages, meaning if I completely uninstall it and reinstall the app, the first few uses are pretty quick and then it gradually gets slower.