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Back-End Development

Duplicate Setting Can Kill You


An Important Question Setting

Imagine that you have a config patch I.Am.The.Only.One.config with:

<setting name="Question.ToBeOrNotToBe" value="false" />

Then for some environments you add Nope.You.Are.Not.config with:

<setting name="Question.ToBeOrNotToBe" value="true" />

You probably wanted it to be:

<setting name="Question.ToBeOrNotToBe" set:value="true" />

but you forgot.

To Be

Sitecore can handle a duplicate setting. It will complain on startup:

WARN  A duplicate setting "Question.ToBeOrNotToBe" has been detected ...

but then it will pick one of the two values and it will keep going just fine.

Not To Be

If you now go to /sitecore/admin/updateinstallationwizard.aspx and try to install an *.update package (any package really, the contents doesn’t matter) you will be very surprised to see that you can’t get past the Install screen. The iframe will behave as if your sitecore site was no longer running and couldn’t be accessed.

In your log file you will find:

WARN  A duplicate setting "Question.ToBeOrNotToBe" has been detected ...
WARN  A duplicate setting "Question.ToBeOrNotToBe" has been detected ...
WARN  A duplicate setting "Question.ToBeOrNotToBe" has been detected ...
WARN  A duplicate setting "Question.ToBeOrNotToBe" has been detected ...
WARN  A duplicate setting "Question.ToBeOrNotToBe" has been detected ...

A lot. I counted some 1500+ lines and then nothing. Void. Application pool got overwhelmed by the question… with all symptoms of a stack overflow.


We were able to reproduce the described behavior and have registered it as a bug. Thank you for reporting the issue. To track the future status of this bug report, please use the reference number 440534

As a workaround, please remove the duplicate setting from the config files.

Thoughts on “Duplicate Setting Can Kill You”

  1. Found this one a few months ago – took me a few tries to realize what was going on. Oddly enough – sometimes it isn’t overwhelmed immediately if it’s a very small package or your site has recently recycled. Sitecore has made some very TDS-unfriendly changes in V8 unfortunately.

  2. Hi Chris,
    I have been using TDS with SC 8 for a while on a project. Can you tell me what changes you are referring to? Maybe we can come up with a solution that helps you out.


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Brian Beckham

As a Sitecore MVP, Brian spends most of his time consulting and architecting software solutions for enterprise-level Sitecore projects.

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