The older version are not El Captain compatible. You will need to upgrade.
Call customer service on the refund issue. I think you get a 60 day trial over that you’d probably have to pay. It may depend on when you bought it.

Resolution for 'Captain compatible issue: 'will intuit refund my money ? i have installed El captain … now quickbooks won’t open…. but i still have to pay?' available: Yes.

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

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