Maybe you need to delete a DLL (or several)?

First of all, back up your files, including your bin folder. You should also back up your database while you're at it (if you haven't already done so).

Next, try a fresh install of Umbraco 7.15.6 on your local machine. Compare those DLL's to the ones on your website. Delete the ones you think may not be appropriate.

You will probably want to do the same for other folders, such as the umbraco folder.

Think that you have 2 umbraco versions in your bin or a server side caching issue.

Think in Umbraco 8 you only have a Umbraco.Web.DLL which is relativly big (> 2 MB) and no Umbraco.dll. On Umbraco 7 you have both but the Umbraco.Web.dll is then very small (< 50 kb).

First do as Nichalas suggest a backup.

Then delete everything inside your App_Date folder.

Also when publishing your solution do you delete everything upfront ?

Also did you do a IISRESET (or stop/start of your virtual directory), or a quick edit of web.config (forcing an IIS RESET).

Also make sure you connect to a previous versus 7 of the database. And in the web.config the add key="Umbraco.Core.ConfigurationStatus" to the correct value.

Hope this helps.

Also in the future also try to setup a test.mysite.com (with basic authentication to prevent indexing from google) to test things so you then just can swap the test and live website without risk or downtime > 1 min.

do you have a backup? Maybe ask hosting comp to restore?

Can you confirm that you've deleted the existing bin folder before copying just Umbraco 7 DLL's over? Also, can you confirm that you are getting the same error after doing so? Where did you get your Umbraco 7 DLL's?

I have an Umbraco 7 website I'm looking at right now and I do not see an Umbraco.Web.dll file in the bin folder. I see Umbraco.Web.UI.dll, but not Umbraco.Web.dll. That makes me think you still have some Umbraco 8 stuff left over that you have not deleted.

The content of the App_Data folder (first backup to be sure) contains cached things (and log files and model), so I would clear this because it gets regenerated.

Not sure which AppModel mode you are using (check settings in web.config) because it can be also generated for Umbraco 8, but if you can login to the backend you can regenerate it there.

Also you can check the log for the specific error your now getting. Also Right clicking on the Visual Studio solution and do a clean solution might help getting rid of some old stuff.

Also do you have everything in 1 project or does your solution consist of mulitple project, if so are all other project converted back to 7 as well ?

if backups are setup you should be able to do it from the portal https://docs.microsoft.com/en-us/azure/app-service/web-sites-restore

Hi, After following the answers in this thread I'm able now to access again the back office (mywebsite.net/umbraco), however, my website is still unavailable.

This is the error I'm getting now (I also tried to run it locally using Visual Studio 2017, by install U7.15.6 using nuget, and also on local I get the same error):

The call is ambiguous between the following methods or properties: 'Umbraco.Web.UmbracoHelper.Media(params int[])' and 'Umbraco.Web.UmbracoHelper.Media(params string[])' Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: The call is ambiguous between the following methods or properties: 'Umbraco.Web.UmbracoHelper.Media(params int[])' and 'Umbraco.Web.UmbracoHelper.Media(params string[])'

Source Error:

Line 20:    var section_node = Umbraco.Content(1xxx);    
Line 21:    var Section_pagesToList = @Section_node.Children.Where("Visible");
Line 22:    Section_pagesToList = Section_node.DescendantsOrSelf().Where("NodeTypeAlias == @0", "NewsPage");

So what I did, I changed Line 21 as follow:

string[] Section_pagesToList = @Section_node.Children.Where("Visible");

But now I'm getting another error in other part of the page - where I display the feature image of this section:

Line 81:                <div class="col-xl-6 col-lg-6 col-md-4 MainNewsBox">
Line 82:                    <figure>
Line 83:                        @if (Section_pagesToList.Last().HasValue("articleImg"))     

The error in line 83 is:

Compiler Error Message: CS1929: 'string' does not contain a definition for 'HasValue' and the best extension method overload 'PublishedContentExtensions.HasValue(IPublishedContent, string)' requires a receiver of type 'IPublishedContent'

What to do?? My website is unavailable for almost two weeks. It's an online magazine and I have advertisers that running advertising campaigns on my website. They pay for banners and their banners are not shown as the website is unavailable. How can I bring it back? I just tried to upgrade to U8 and now I can't bring my website back.

Thanks (again) for your help

Can you share the entire contents of the CSHTML file you're having an issue with? What you've shared so far doesn't make a lot of sense to me. For example, the first error message mentions the function Umbraco.Web.UmbracoHelper.Media().

The problem with that is that your line 21 does not using the .Media() function. Line 20 does use .Content(), but not .Media(). So I'm curious if it was actually line 20/21 that had that error, or if it was some other line.

Secondly, I'm not sure why you would use string[] as the data type for this line:

string[] Section_pagesToList = @Section_node.Children.Where("Visible");

That should return a IEnumerable<IPublishedContent> rather than string[], so the var should have been fine to use.

While it probably doesn't matter, I see no need for the at sign in @Section_node. It might be necessary if you called the variable @Section, but not for Section_node.

The HasValue error is clearly because you used string[] as the data type.

If you share the contents of the file, that'd probably go a long way toward figuring things out.

It would also be useful if we could see your web.config, but you'd want to scrub any sensitive details (e.g., SQL connection string credentials). And be sure it's your actual web.config from production, rather than your local copy.

I see a number of calls to Umbraco.Media in the HP_Photonics_Lasers.cshtml file, but this line (line 31) is the only one without a null check:

<img src="@Umbraco.Media(feature_story_HP.articleImg).Url" alt="@feature_story_HP.photoAlt" class="img-fluid news-img" />

Maybe add a null check and see if that helps.

Also, if you know the return type of statements like feature_story_HP.articleImg, you can cast it to be more explicit so the call is not ambiguous. For example, you could change the above line to something like this:

<img src="@Umbraco.Media((int)feature_story_HP.articleImg).Url" alt="@feature_story_HP.photoAlt" class="img-fluid news-img" />

Or, if you know it's a string, it'd be more like:

<img src="@Umbraco.Media(feature_story_HP.articleImg as string).Url" alt="@feature_story_HP.photoAlt" class="img-fluid news-img" />

You could temporarily delete the problematic lines and output some debugging code for testing purposes. For example, you could comment out the above line and write something this to get the data type (I don't have an IDE open, so the property may be something else, such as FullName):

@feature_story_HP.articleImg.GetType().Name

In the case of null, that'd throw an exception, which would also be useful information to assist with troubleshooting.

Good luck.

* UPDATE * My website is back in the air.

What I did is, I downgraded to 7.11, 7.8, then upgraded again to 7.15.6 and somehow my website is back in the air again.

It was very frustrating, but finally my website is again in the air, online.

What I learned from this experience?

Now on when I upgrade to a version with a major change - for example, 7 to 8, I'll first do it locally on my machine, then only when verifying locally that everything is working, only then deploy to production (I used to do everything until now on direct production... - yeah yeah, I know, very unprofessional, but you know how it is, when it's not work and only my personal website, I didn't really follow the "rules" ... - I guess there's a (good) reason for why and how to do things in the right way)

Maybe I'll even create another environment, something like - test.mywebsite.net so I can deploy first to test, then if everything is working, to production.

I also think to try create a pipeline, maybe with gitlab or something where instead to update the code on umbraco back office, to have a local git repository, to push to remote, then create kind of automation. But I need to check it.

Thanks again for all the help.

is working on a reply...