After you upgrade to Microsoft SQL Server 2012 Analysis Services (SSAS 2012) from Microsoft SQL Server Analysis Services (SSAS), some UPDATE CUBE statements may not be successfully executed. Additionally, you receive the following error message:
Errors in cell writeback: Unable to write back as the weight expression does not return a decimal value between 0 and 1.
This issue occurs because of an improved validation on the weight expression that is added in SSAS 2012. This weight expression should be expressed as a decimal value between 0 and 1.
Cumulative update information
Cumulative update 3 for SQL Server 2012 Service SP1
The fix for this issue was first released in Cumulative Update 3. For more information about how to obtain this cumulative update package for SQL Server 2012 SP 1, click the following article number to view the article in the Microsoft Knowledge Base:
2812412 Cumulative update package 3 for SQL Server 2012 Service Pack 1Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2012 SP 1 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2772858 The SQL Server 2012 builds that were released after SQL Server 2012 Service Pack 1 was released
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.