Can I use PCT-SAFE (not in PCT-EASY mode) for filing PCT applications via EFS-Web?

No. The "fully electronic" filing functionality of PCT-SAFE is disabled where the U.S. is selected as the Receiving Office. EFS-Web will only allow submission of the PCT-EASY .zip file created by PCT-SAFE when operated in PCT-EASY mode. (When a resident and/or national of the US files a PCT application in the United States Receiving Office, and Applicant includes the .zip file containing the PCT Request and the Abstract, using the PCT-SAFE software, then the Applicant is entitled to a $155 reduced international filing fee for filing in both EFS Web and using the PCT-Safe software.) PCT-SAFE when operated in PCT-EASY mode creates a validated Fee Calculation Sheet and a PCT Request which will entitle you to a 200 Swiss franc reduction of the international filing fee. All other documents or application parts (e.g., description, claims, drawings and abstract) must be separately prepared and attached as PDF documents. (This discount would only apply if applicant was using the IB as the Receiving Office.) If you choose not to use PCT-SAFE to create the Request and Fee Calculation Sheet, you can use the conventional Request (Form PCT/RO/101) and attach it as a PDF document in the same way all other documents or application parts are attached (e.g., description, claims, drawings and abstract).

USPTO FAQ - Questions and Answers (2008APR04)