Run  a quick report on the assembly item, set the date range to ALL.  For the date of this build, was the assembly item showing a negative qty on hand?

One reason this can happen is that the assembly item was negative on hand.  When that happens QB still posts the […]

Resolution for 'Building assemblies issue: 'Building assemblies creating a negative (credit) balance' available: Yes.

The Building assemblies issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the Building assemblies issue yourself by looking for a resolution described in the article. If it is a complex Building assemblies issue or you are unable to solve the issue, you may contact us by clicking here or by using other Building assemblies support options.

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