What was going on when you received the error?

If you were attempting a payroll update, see this:  https://community.intuit.com/articles/1436388-error-15106-when-updating-quickbooks-desktop

Resolution for 'code 15106 issue: 'how do i resolve error code 15106' available: Yes.

The code 15106 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 code 15106 issue yourself by looking for a resolution described in the article. If it is a complex code 15106 issue or you are unable to solve the issue, you may contact us by clicking here or by using other code 15106 support options.

For more information about resolving issues related to code 15106 in Quickbooks/QBO or to get support for the issue 'how do i resolve error code 15106', click the link below: