Does AV access sandbox

If a file that looks like a virus but is not is run manually in the sandbox will the antivirus delete it as it would outside the sandbox?

If so, is there a way to prevent the av detecting inside the sandbox?

In case you are convinced the file is not a virus you can add it to the AV exclusions. You can also report it to Comodo as false positive from within CIS.

However the best way to report a false positive in the AV False Positive/Negative Detection Reporting board.