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Resonance lines of $^7$Be are detected currently in five novae. Availableabundances for this isotope estimated from equivalent widths of $^7$Be\,II andCa\,II lines are significantly higher compared to predictions of models for thethermonuclear flash. In attempt to pinpoint the reason for this disparity weexplore the possibility for the higher $^7$Be yield via computing kinetics ofthe thermonuclear burning in the framework of two-zone model and find that evenfor a favorable choice of parameters $^7$Be mass fraction does not exceed$3\cdot10^{-5}$. This is consistent with known theoretical results and leavesthe disparity between the theory and observations unresoved. We find that thecontradiction is caused by the assumption that the ionization fraction ofBe\,II/Be is equal to that of Ca\,II/Ca, which has been adopted formerly inorder to estimate the $^7$Be abundance. In the case of nova V5668 Sgr theionization fraction of Be\,II/Be turns out to be at least by a factor of $\sim10$ higher compared to Ca\,II/Ca due to the difference of ionizationpotentials. Our new estimate of the $^7$Be mass fraction for nova V5668 Sgrdoes not contradict the theory. The calculated flux of 478 keV gamma-quantafrom the $^7$Be decay is consistent with the upper limit according to {\emINTEGRAL} observations.

$^7$Be abundance in nova V5668 Sgr doesn't contradict theory