I have built a dnn 6.2.3 site on local IIS server, let's call it  [site.local].

After successfully launched it live on web server, (call it [site.com]), I started to keep both site in sync by restore the backup copy of live SQL DB from live site.com.

Well, suddently, the [site.local] lost the CSS style. But it only has this porblem before I login as a registered user. Everything looks perfect after I login.

I tried removing the site.local from IIS, and rebuilt a new one from the copy of the live site. It didn't work.

Any advice? Thanks!

Thank you, Sebastian.

Yes, the .css files are there in the file. For example, home.aspx. Problem is, it totally no CSS style before login, but looks perfect after login as registered user.

I believe I found the cause of the problem. The permission for the css files.

At live website, if I type in: http://URL//Portals/0/portal.css, I can see the source code.
As local site, if I type in: http://URL//Portals/0/portal.css, I get the messed up login page.

Same thing happens to the images on the webpage. I will be led to login page if I type a direct link to the image.

But question is, the problem is not 100% persistence. I can get some images displayed 1 or 2 out of 10 visits.

I've tried to reapply the permission for the pages, make sure they are visible to all.

I've tried clearing browser cache, and tried on 4 major browsers. The website is fresh duplicated from live site which perfectly normal. What else could I do? At local server, I tried connect to Database using "sa" account.

Shall I reinstall the whole server?

Oh, MY!! You hit the jackpot.

Well, yes. I installed this website on a separate drive other than inetpub\wwwroot. Because I normally keep all data off windows disk for easy data backup. And did set the rigth property for IIS, just the property for DNN.

Thank you so much for your help.