”Webpage is slowing down your browser” This is the new way the browser tells you there is a problem with the script program(s). https://support.mozilla.org/en-US/kb/warning-unresponsive-script?cache=no

I don't use Xmarks, but their extension in Firefox appears to be slowing Firefox down when loading the Home Page - assuming that is upon "launch" of Firefox as the "New Tab" page appears on the only Tab and it is empty of the usual New Tab data. Plus, the "launch" process was changed for Firefox 57, which IMO could be why that "Web page is slowing down your browser." message may have just begun happening with Firefox 57 and not with earlier versions, if that is the case. New Tab was changed a lot and wasn't used in lieu of the "Home Page" in past versions.

My thoughts are that the Xmarks extension is attempting to contact the Xmarks server to early in the "launch" process and should be delayed a few seconds as Mozilla has done in Firefox with Sync and with "check for updates" inside of Firefox.

FredMcD said

”Web page is slowing down your browser” This is the new way the browser tells you there is a problem with the script program(s). https://support.mozilla.org/en-US/kb/warning-unresponsive-script?cache=no

Thanks

The Letting the script run longer doesn't work. I set the integer value to 20 as suggested. Still get the error message.

Installed the JavaScript Toggle. This also doesn't seem to work.

the-edmeister said

I don't use Xmarks, but their extension in Firefox appears to be slowing Firefox down when loading the Home Page - assuming that is upon "launch" of Firefox as the "New Tab" page appears on the only Tab and it is empty of the usual New Tab data. Plus, the "launch" process was changed for Firefox 57, which IMO could be why that "Web page is slowing down your browser." message may have just begun happening with Firefox 57 and not with earlier versions, if that is the case. New Tab was changed a lot and wasn't used in lieu of the "Home Page" in past versions. My thoughts are that the Xmarks extension is attempting to contact the Xmarks server to early in the "launch" process and should be delayed a few seconds as Mozilla has done in Firefox with Sync and with "check for updates" inside of Firefox.

Thanks for the info.

I have been in contact with Xmarks support. I really don't think they what is causing the sync issue. My opinion.

Everything you mention is exactly what I have going on. I think I may have to find another bookmark option. Any suggestions??? Doesn't FireFox offer any bookmarks like Microsoft edge or Explorer?

Thanks again.

Besides Xmarks issues having too many running Addons also can be problem if they are running when they shouldn't be. How about disable all of them except xmarks and why syncing does the problem persist?