This database has a persisted computed column, which is computed by calling a .NET function. When changing compatibility from MSSQL 2005 to 2012, I was presented with error 10334, which looks more like a warning: it's telling me that it had to mark one of the tables as has_unchecked_assembly_data.

What it doesn't tell me is what to do about this. Should I leave it as is? Should I force the column to be recomputed somehow? How?

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The documentation for alter assembly unchecked data lists several causes for this, and I think #1 is the only one that applies to this database. It also doesn't explain how to unmark such columns.

  • 1
    DBCC CHECKTABLE or DBCC CHECKTABLE will set the has_unchecked_assembly_data to zero according to msdn.microsoft.com/en-us/library/ms187406.aspx.
    – Dan Guzman
    Commented Nov 24, 2015 at 13:10
  • @DanGuzman It did, thank you! I did a fair bit of googling but couldn't find this. I'll accept if you post as an answer. Commented Nov 24, 2015 at 13:47
  • @romkyns Just FYI, the documentation that you linked to for ALTER ASSEMBLY actually does explain this fix: UNCHECKED DATA: By default, ALTER ASSEMBLY fails if it must verify the consistency of individual table rows. This option allows postponing the checks until a later time by using DBCC CHECKTABLE. ;-) Commented Nov 24, 2015 at 14:16
  • @srutzky hah! You're right. I did not recognize that as an SQL command, nor did it occur to me to google that. Commented Nov 24, 2015 at 14:17

2 Answers 2


Execute DBCC CHECKTABLE or DBCC CHECKDB to set the has_unchecked_assembly_data to zero. This is documented in the SQL Server Books Online sys.tables reference.

  • I think you have the DBCC listed twice ;-). Also, this fix is documented in the ALTER ASSEMBLY documentation under the UNCHECKED DATA option. Just mentioning that for completeness :-). Commented Nov 24, 2015 at 14:18
  • @srutzky, thanks for pointing out the typo. Corrected.
    – Dan Guzman
    Commented Nov 25, 2015 at 4:16

While Upgrading to SQL Server 2017, i needed to run DBCC CHECKDB or DBCC CHECKTABLE with the EXTENDED_LOGICAL_CHECKS option to set has_unchecked_assembly_data to zero.

Assemblies - Implementing
Performing Logical Consistency Checks on Indexes

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