However, there may be several drawbacks to this approach, including the following:
An applicant must choose between adjustment of status (I-485) and consular processing, and cannot do both. By choosing consular processing, the applicant gives up the right to obtain an employment authorization document (EAD) while the application is pending. For that reason, we do not recommend consular processing for those with less than 18 months left before their H-1 or L-1 visa finally expires.

The consular processing times could also increase. If the delay at the INS persists, tens of thousands of applicants could seek the alternative of consular processing, creating substantial backlogs at the U.S. Embassies and Consulates as well.

Except for U.S consulate in India, there could be substantial delays in transferring the approved I-140 from the INS to the U.S. embassy or consulate. Currently U.S. consulates in India will accept Attorney-certified copies. However U.S. consulates in other countries may require an additional application (I-824) to be filed with the INS to request transfer of the file to the National Visa Center (or "NVC") in New Hampshire. In many cases, the INS can take up to nine months or more to process the I-824 and to send the I-140 to the NVC. The NVC can then take another three or four months to process the case and send it to the U.S. Embassy or Consulate. The NVC processing time could also increase if a significant number of applicants choose consular processing instead of the I-485.

An interview is required at the U.S. Embassy or Consulate and the applicant’s appearance is generally required for the entire day. In contrast, an interview in connection with an employment-based I-485 is rarely required.

The applicant must travel to the consulate on short (two or three week) notice, which often requires purchasing an airline ticket at the highest price.

The applicant must arrive at the city in which the U.S. Embassy or Consulate is located at least several days before the interview for a medical examination. The time required to be spent in that city (and away from work) may therefore be as much as a week or more.

Additional documents such as home country police clearances and military service records may be required.

If a problem arises at the interview (such as a missing document or an issue involving a prior application for a visa) the applicant may be stuck outside of the United States until the problem is resolved.

If the application is denied, there is little or no right to review or appeal. In contrast, if the I-485 is denied, the applicant has the right to renew the application in removal proceedings, and has several options for review and appeal. Generally the applicant may remain in the United States with employment authorization while those proceedings are pending.