About 235,000 BTec Firsts, Technicals and Tech Award grades were scheduled to be sent to students. But exam board Pearson said that 7,000 students were "ineligible to receive their grade".
About 235,000 BTec Firsts, Technicals and Tech Award grades were scheduled to be sent to students on Thursday.
But exam board Pearson said that, as of Wednesday morning, 7,000 students were "ineligible to receive their grade".
Pearson said it had "a dedicated team" working to obtain any outstanding information and would provide any results "as quickly as possible".
Results for GCSEs, as well as other vocational and technical qualifications, are also due to be released on Thursday.
Pearson's announcement does not affect results for GCSEs.
The affected BTec students could be deemed "ineligible" because some of their marks are not logged in the system, the BBC understands.
This may be because of processing issues, or, in some instances, because the pupil has decided not to continue with their BTec studies.