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Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition

Symptoms
When using VS.NET Web Developer Express Edition, you may have a site that compiles fine in the development environment but fails when you copy it to the local IIS server.

Cause
ASP.NET 2.0 is not the default .NET version used by IIS.  It works in the development environment because VS.NET compiles a virtual web server with the proper .NET version before code compilation begins.

Thinking it occurred because the virtual directory wasn't identified as an application, I created a site (called personal) that mapped to the directory I copied, but still failed.

As it turns out, 'xmlns' is a component in ASP.NET 2.0, and will generate that error when compiled on an IIS server running ASP.NET 1.1.  This is delightfully easy to fix:

  • Open Internet Information Services and navigate to "Default Web Site" (or the site you're using as your default).
  • Right click the Site icon (the one with the globe).
  • Select the ASP.NET tab.  You'll see a drop-down with the available versions (if you're getting the error, odds are, you'll see 1.1).
  • Select the proper build of ASP.NET 2.0.
  • Restart IIS.

Your page should now work.

posted on Sunday, August 21, 2005 9:35 AM

Feedback

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/4/2005 9:35 AM Paul Campbell

Legend!

Thanks man - very helpful

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/7/2005 8:36 AM Raj

(FORGOT TO ADD THIS: PLEASE EMAIL ME AT raj@rhealsoft.com or raj@xtremebiz.biz if you have a solution for this)

hi,

can you help me with this:

i have an asp.net 1.1 application folder inside an asp.net 2.0 application folder.

although i have set iis to run the 1.1 application folder under asp.net 1.1 dll, when i try to access my 1.1 application, i get the same xmlns runtime error.

this is happening because asp.net 1.1 first tries to read the web.config of the upper level folder which infact is 2.0 application's web.config file and so it cant recognize this. is there a work around for this

thanks in advance,
raj

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/7/2005 10:14 AM opsan

That is really interesting; can you run a 1.1 application inside a 2.0 folder? Is the 2.0 folder a virtual directory? If so, I -think- it'd be recognized as a 2.0 application.

That said, what is your need to have a nested 1.1 application? If you run the 1.1 application in it's own 1.1 folder, does it function alongside your 2.0 environment? I would expect IIS to support that.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/10/2005 7:34 AM John Doe

Can't you just add a new web.config file in the ASP.NET 1.1 directory? It should use that file rather than the root web.config.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/10/2005 8:09 AM opsan

Great suggestion; does that work? I seem to recall being able to assign custom .config files rather than the standard web.config, which might also allow.

I guess I don't quite understand the problem space; maybe Raj can enlighten us.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/10/2005 8:16 AM adam

Thanks a bunch. You are a real life saver.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/18/2005 6:20 AM Chris

Thank you very much, I was getting quite frustrated with this error!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/26/2005 3:34 AM Jim Sneeringer

I have the same error message, but there is no ASP.NET tab. When I look under C:\WINDOWS\Microsoft.NET\Framework, there is no folder for .NET 2.0, but when I try to reinstall .NET 2.0, it tells me it is already installed. I went to Add/Remove programs to try to uninstall, but only 1.0 and 1.1 are there.

Anyone have any ideas?

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/26/2005 4:05 PM opsan

It does sound like .NET 2.0 is not installed; is it possible you installed a beta version at one time or another?

Are there any other post-.NET 2.0 programs installed? WinFX beta, perhaps?

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 11/30/2005 2:02 PM Matthew Parker

Thanx for the help, solved my problem

# Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 12/18/2005 12:48 AM Anil Kumar

Iam using XP O/S with
.NET Framework 1.1 Configuration

(version 1.1.4322.573

An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Unrecognized attribute 'xmlns'

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 12/18/2005 8:55 AM opsan

Anil, if this is request for assistance, this article covers your issue. Please step through it and advise if it doesn't resolve the problem.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 12/19/2005 1:53 PM unfrustrated

It worked, thanks!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 3/8/2006 5:19 AM Taj

Thanks

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 4/15/2006 8:23 AM Thiru

Amazing post....i searched for two days to fix this problem.....great...thanx...

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 5/11/2006 8:30 AM Daniel

Strange! When I follow the advise and change the ASP.NET version under the ASP.NET tab of the Default Web Site Properties from 1.1 to 2.0 this does not have any effect. Instead, after restarting IIS the ASP.NET version is switched back to 1.1

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 5/11/2006 8:48 AM Daniel

Found the reason!
When restarting IIS the ASP.NET version seems to be switched to 1.1 whenever there is at least one application that is set to 1.1

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 5/15/2006 8:39 AM Andrea

Thanks!!! Very Helpfull

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 5/29/2006 4:36 AM Sarfaraz Baldiwala

Hi,all
The solution worked out. Thanks

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 6/16/2006 7:49 AM puja

Thanks! Worked after setting to ASP.Net 2.0

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 7/20/2006 2:59 PM FEVuser

Sorry,

i tried everything mentioned in this thread:

for me it won't work.

I have a hibernate config section in the web.config file; i setted IIS to 2.0 (+ restart) i get the same error.
when i cut out the "xmlns"-tag, i recieve ""Unrecognized element."

Any idea ?

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 8/22/2006 3:27 AM mcg

good man - thanks for the tip!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 9/13/2006 7:44 AM shoge

Its good , I had the same issue and its working now

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 9/15/2006 10:04 AM Brandon

Thanks a ton. This solved my issue.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 9/18/2006 8:11 AM PJ

Since there are some quite recent comments here, I'll add my two-pennorth:

Thanx for this - but I can'tell whether it's helped, as, updating to ASP 2.0 gives another, bigger error (so my error is bigger than yours!)

I get

Exception Details: System.Web.Hosting.HostingEnvironmentException: Failed to access IIS metabase.

The process account used to run ASP.NET must have read access to the IIS metabase (e.g. IIS://servername/W3SVC). For information on modifying metabase permissions, please see http://support.microsoft.com/?kbid=267904.

Various fiddles using aspnet_regiis (as suggested by oth bloggers) don't seem to work.

Any suggestions?

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 10/13/2006 10:12 AM robert fisher

That was my issue.

Thanks.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 1/14/2007 3:16 AM Doug P

If you don't have the asp.net tab then it might just be that you had IIS manager open before you installed .NET 2.0 and haven't restarted it... That's what happened to me. The advice in this thread was a great help. Thanks.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 1/31/2007 7:44 AM Donovan Buck

Thanks for that tip Doug P (that slap you just heard was my hand hitting my forehead)

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 2/20/2007 9:24 AM Nelman

Thanks for the help. I was having the same issue with a personal website and the above solution worked. Thank you!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 2/26/2007 7:14 PM SWSS

Thanks for the help your a Legend!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 3/1/2007 12:11 AM Lata

Thanks .....U are Master.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 3/1/2007 6:34 AM Ichi Olocco

Excelent! Thank a lot!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 4/9/2007 11:22 AM harikrishna p

thanks it works

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 4/17/2007 3:24 AM secure email

Yep, that work. Was under the assumption that IIS is getting it automatically. Using normally HELM to administer all my sites and forgot to switch ont the ASP.NET 2.0 Checkbox.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 4/18/2007 6:30 AM WillC

So simple - many many thanks!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 5/28/2007 4:03 AM Johnny

Nice!! Jackpot!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 6/12/2007 3:20 AM Dipesh

i am having the same problem the web server is on 2.0 but i still get this error "Unrecognized attribute 'xmlns'. Note that attribute names are case-sensitive." i dont even have 'xmlns'in the web.config file please help... :0(

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 6/19/2007 1:57 AM KiranSabinkar

Thanks. It works.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 6/22/2007 2:04 PM TexasPRd

I'm in VS2005, but not using IIS. I've been using the ASP.Net Development Server. How can I get around this problem in my environment? Thanks!

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 1/1/2008 3:24 AM irwanmohi

i have try your solution, but i still can`t fix the issue.

thanks

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 2/19/2008 4:00 AM Kj

Thanks a lot man. You saved me a lot of time.

# re: Unrecognized Attribute 'xmlns' when working with VS.NET Express Edition 4/25/2008 7:43 AM Srikanth

Go to your Dotnet 2.0 framework directory for example: "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727" and run aspnet_regiis /i command this will resolve your problem.

Srikanth

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