I think it is unlikely that a Windows update has caused your problem (although I'm not sure what might be causing your problem).

First of all, please try clearing your browser caches before reloading your gallery's web page to see if this makes a difference.

Also, if you have any browsers extensions installed, please try temporarily disabling them to see if this helps.

If you still cannot view your gallery in certain browsers, then please post a link to your gallery's web page so that I can take a look at the problem for myself. (You should be able to view your gallery in all major modern browsers: Chrome, Edge, Firefox, IE8+, Opera, Safari.)
Once I'm able to see your gallery, I should hopefully be able to determine the cause of your problem and propose a solution.

Yes.
Please see here for the Juicebox System Requirements.

I'm glad that you've been able to resolve your problem.
Thank you for letting me know.

Good news! I have heard back from Avast and they have now cleared the JuiceboxBuilder-Lite executable file's reputation in their database.
They say that the change may take up to 24 hours to take effect so, hopefully, you should have no problem running JuiceboxBuilder-Lite alongside Avast's Ransomeware Shield after your Avast database is next updated.

Thank you for the clarification.
I'm glad you've found a workaround (even though it's not ideal).

As I mentioned, if the problem is with the way that Lightroom handles the generation of the gallery files (either a timing or multi-threading issue), then there is perhaps little that can be done from within the plugin to counteract this.

However, if it will help, I could compile a version of the plugin for you which would not update the live preview window automatically when each configuration option is changed in the interface. Instead, the live preview window would be updated only on demand (Cmd+R (Mac), Ctrl+R (Windows), 'Web -> Reload'). This would drastically reduce the number of times that Lightroom regenerates the gallery's 'config.xml' file for the preview and should help with the problem (although you'd not see the changes you make to the gallery instantly).
If you'd like me to do this for you, then please let me know.

In the meantime, please let me know how you get on with the plugin on your Windows system.
Thank you.

I'm glad to hear that you've found the root of your problem.
Thank you for taking the time to post back to let me know. It's most appreciated.
Thanks also for taking the issue up with Avast. Please let me know how you get on.

I'm not sure if you are referring to the "Config file not found." message appearing in your Chrome browser or Lightroom's live preview window (or both).

If the error message appears in your Chrome browser, then please see this FAQ which refers to the error message and might help.
When I view my gallery I see the message 'Config file not found'. How do I fix this?

Also, if possible, please upload the gallery to your web server and post a link so that I can take a look at the problem for myself and hopefully help further. Once I am able to see your gallery and its code, I should be able to determine the cause of the problem and propose a solution.

If the error message appears in Lightroom's live preview window then the try forcing a refresh of the page (by pressing Cmd+R (Mac), Ctrl+R (Windows) or by selecting 'Web -> Reload' from the drop-down menu at the top) to see if this clears the problem without having to move away from the Juicebox web engine and lose your settings.

Over the course of a year and a half, only three other users have reported the "Config file not found." message appearing in Lightroom's live preview window. Two of these users are known to be using a Mac (the third user's system is unconfirmed) but I've never been able to replicate the problem myself on a Windows PC. From the limited information I have, it seems that the problem may affect only a limited number of Mac users.

Maybe my notes in these forum threads will at least help to explain this issue in greater detail:
https://juicebox.net/forum/viewtopic.php?id=2115
https://juicebox.net/forum/viewtopic.php?id=2249

As I mentioned in the forum threads above, the problem could be some kind of timing problem with the way that Lightroom generates the files for the preview (perhaps the 'config.xml' file is sometimes not ready in time for the gallery to be displayed by the 'index.html' file).
In the plugin's manifest file, the plugin requests that the 'config.xml' template be processed before the 'index.html' template so, unless there is some kind of threading issue or asynchronous activity (which, as far as I am aware, the plugin has no control over), I'm really not sure what might be causing the problem.

Please let me know if refreshing the live preview window when the error message appears (Cmd+R (Mac), Ctrl+R (Windows), 'Web -> Reload') helps.

You're welcome!

I'm glad you've found the cause of your problem, although deselecting the "Include xmp metadata in generated images" checkbox should not prevent an image from being processed and placed into the 'hi-res' output folder.
As the relevant post is already in jAlbum's 'Bug reports' sub-forum and the problem you reported is clearly the same as that of the original poster, I would normally suggest that you bump the post (it's not that old) and add your own notes to make your voice heard and to let the jAlbum developers know that there is at least one other user who is affected by the problem.
However, as the jAlbum team are removing the ability to generate 'hi-res' images in the next version of their program, I think it is highly unlikely that they will spend time and resources fixing a bug relating to a feature that will not be around for very much longer so there's probably very little you can do other than deselecting the "Include xmp metadata in generated images" checkbox (or adding you PNG files manually to the 'hi-res' folder after album creation).

Deselecting the "Include xmp metadata in generated images" checkbox just means that there will be no embedded data (at least not in XMP format) in the album images.
If all you want to do is display your images in a gallery, then there will be no functional problems at all.
However, some people might prefer their images to contain metadata (such as a copyright message and/or information about the image) but this has no effect on the visual quality of the images in the gallery or the functionality of the gallery itself.

I notice you use a galleryHeight of 50%.
This suggests that the gallery's actual height should be only 50% of the height of its parent container (and this would likely result in unwanted space).

Also, when using a percentage height, you'll need to make sure that all the gallery's parent containers have heights assigned via CSS, otherwise the browser may not be able to determine what the gallery's actual height should be. (The browser needs to know what the gallery's height should be 50% of.)

Additionally, you might need to take into account this note regarding Using Percentage Heights.

You might like to try setting your galleryHeight to 100% (so that you know that the gallery will always fill the height of its parent container) and then adjust the height of your gallery's parent container(s) as necessary.

Otherwise, to avoid the potential problems associated with using a percentage height, I'd recommend setting your galleryHeight to a fixed pixel value (such as 600px).
In doing so, you will have total control over the height of your gallery (you always know how high it will be), and being that your web page has a lot of vertical scrolling content, your gallery would not benefit from being responsive in the vertical dimension.
At the moment, the height of your gallery (and the amount of space above and below the main images) changes depending on the height of the browser window. I expect you probably do not want this to happen and a fixed height gallery would be the solution. (A vertically responsive gallery would really only be useful if your web page's content filled the browser window without any vertical scrollbars.)

Try using something like the following (adjusting it if necessary) and hopefully you'll be able to reduce the space surrounding your images.

galleryHeight: "600",

Facebook uses the data from Open Graph meta tags to populate the sharing window.

The thumbnail image displayed in the Facebook sharing window is determined by the og:image tag.
This specified image is displayed when any image in your gallery is shared.
You can think of the og:image as being representative of the gallery as a whole so you could use an image which best represents your gallery. (The og:image does not need to be an image from the gallery itself.)

When you create a Juicebox-Pro gallery with JuiceboxBuilder-Pro, Open Graph tags are included in the gallery's 'index.html' file (and the first image in the gallery is used as the og:image Facebook thumbnail).
The tags will looks something like this.

<!-- START OPEN GRAPH TAGS-->
<meta property="og:title" content="This is the Gallery Title." />
<meta property="og:type" content="website" />
<meta property="og:url" content="http://www.example.com" />
<meta property="og:image" content="http://www.example.com/images/IMG_0001.jpg" />
<meta property="og:description" content="This is the Gallery Description." />
<!-- END OPEN GRAPH TAGS-->

og:title uses the Gallery Title ('Customize -> Lite').
og:url uses the Share Url ('Customize -> Sharing').
og:image uses the Share Url and appends the relative path to the first image in the gallery.
og:description uses the Gallery Description ('Customize -> General').

If you embed your gallery into a custom web page (and do not use the 'index.html' file generated by JuiceboxBuilder-Pro), then you'll need to manually add an og:image meta tag to your web page. Please make sure that the content is in the form of an absolute URL (such as http://www/example.com/images/image.jpg) and not a relative URL.

If, after adding an og:image meta tag to your web page, you do not see the specified image displayed in the Facebook share window, then you might need to use one or more of the following online tools that Facebook provides.

(1) Facebook's Sharing Debugger: https://developers.facebook.com/tools/debug/sharing/
(2) Facebook's Batch Invalidator: https://developers.facebook.com/tools/d … ing/batch/
(3) Facebook's Open Graph Object Debugger: https://developers.facebook.com/tools/debug/og/object/
(Click the 'Fetch new scrape information' button.)

Running your web page's URL through these online tools should clear Facebook's cache of your web pages and fetch new scrape information from your gallery's web page.

Hopefully this will help.