We have SharePoint Online Tenant with classic features. We have not customised anything on https://domain.sharepoint.com and it is a classic team site as shown in picture. enter image description here

Page is loading very slow in Internet Explorer but in Google chrome it works fine. when i try to use Developer Tool in IE i have found CoreV15 and QCB.css is loading twice and second load is coming from an XMLHttp request which holds the page for few seconds. I understand from other articles that theming.js will be calling again corev15.css internally from the code.You can see even corev15.css is coming from Disk it takes more than 5 second to get the response.

can anybody had the same issue earlier. do i need to change some global settings or something related to the Browser. any kind of suggestion is appreciated.

Addition information- system is Window7 with 4 GB RAM and governed by Corporate Policy.

Console Error as requested enter image description here

  • Which version of IE are you using? From the screenshot i am thinking you are using IE 10, is that correct? Oct 31, 2019 at 12:29
  • IE acts crazy everytime I use it in either SP, OneDrive, etc. I'm curious about those 3 console errors. Anything you want to share? In terms of suggestions, maybe ensure all domains are trusted and also have a look at compatibility mode, stackoverflow.com/questions/25557299/… Oct 31, 2019 at 12:30
  • @Johan its in IE11 in Windows7 Oct 31, 2019 at 14:38
  • @TiagoDuarte which domains you are expecting to trust. i have .Sharepoint.com is in trusted site list. Oct 31, 2019 at 14:43

1 Answer 1


I'm not going to pretend I know what's happening: I don't.

However, I wanted to provide some suggestions that are difficult to place in form of a comment.

  • Fix console errors

Often if there is an error, it might prevent a smooth transition of the remainer of the website. This stack overflow post shows promissing results for covering fonts not loading in IE11 due to group policy settings. Obviously, this may or may not have a direct impact on your main issue(s).

Also, note that the version of the browser and the render mode are two separate things. Open the developer tools (F12) and pick "Emulation" to check the actual modes the current site/page is using.

This used to be a great deal a while ago, not sure if it still makes sense today, but advise to have a look.

Pages will run in Compatibility View unless they explicitly specify another document mode. This option can be disabled using the Tools > Compatibility View Settings menu.

  • Trust Settings/Zones

There are dozens of domains used by SPO/O365 for various sorts of things. While it could be seen as a bad practice, you could try adding those domains to the trust site list as a test and document the results. e.g.

  • sharepoint.com (used by QBC.css)
  • office.com
  • sharepointonline.com
  • msocdn.com
  • office365.com
  • microsoft.com

others (ondrive, etc)

  • live.com
  • ldrv.com
  • livefilestore.com
  • sfx.ms

More on this,



I performed a small test on a Documents library in classic mode (O365) and while the whole page takes long to load with many resources, the QCB.css gets cached and poses no issues whatsoever.


I'm no security expert so while the above might help mitigate the problem, be careful when planning changes to your organisation. I'm merely trying to help.

  • Thank you so much Tiago for detailed Answer. Nov 1, 2019 at 9:29
  • Console Error: It comes even a system which is outside of our network and connected to Wifi. I have gone through Article before but in Windows 7 "Untrusted Blocking Font" registry details is not there. Nov 1, 2019 at 10:07
  • Compatible Mode :IE-Edge i think that is the max available in IE Version of Windows7 Nov 1, 2019 at 10:18

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