Validation of viewstate MAC failed error

This post applies to HPRM 8.1 with SharePoint 2013

In some scenarios, if you attempt to manually manage one or more items, after you click “OK” on the confirmation dialog, an error is shown in the dialog similar to this one:

Server Error in '/' Application.

Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
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: System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Truncated…

Despite this error, a job gets added to the queue and the item ultimately gets managed (barring other issues).

This is a known issue that has been fixed and is due for release in the 8.1 “Multi language” release early in Q4. In the meantime, the work around for this is to modify the web.config file used by the “HP Records Manager SharePoint Server” site on each HPRM server in the HPRM farm.

This work around is a temporary one only. I recognise that there are security implications with doing the steps below and would recommend only doing this change on an internal only system with the view to upgrading to the multi language release with this fixed as soon as it is available.

Locate the “pages” element in the “system.web” node:

Modify the “pages” element to include: enableViewStateMac="false"