The paper looks into the main factors that exert negative influence upon national economies during an economic crisis. Conditions in which the unstable state of the external environment may lead to the aggravation of recessions and entering the stagnation phase are examined. Such situation is demonstrated on the example of the Russian economy. The author has developed an approach and measures for surmounting negative factors of the external environment during the realization of the competitive strategy of a high-technology enterprise in order to ensure the economic adaptability of the enterprise management system to changes in the external environment An array of unorthodox measures, embodied in managing adjustments of the competitive strategy of the enterprise, is proposed. Toward this end, the conditions for realizing adjustments of the competitive strategy are formulated, and stepwise adjustment, conducted by the high-technology enterprise in the crisis period, are substantiated. The expediency of using a value-based mechanism of managing the competitive strategy of the high-technology enterprise via integrating different business units into a holding structure is demonstrated for the conditions of the high uncertainty and external environment instability. The creation of such innovative system of managing a high-technology enterprise facilitates a sustainable and efficient functioning of the newly-formed structure. This enables to secure saving or increasing the market value of the enterprise in the long term in the conditions of limited external financing resources.