这里有两个不同的问题：
1. 如果I-485 pending时失去身份，会不会影响I-485？
答案是不会。对于I-485资格来说，只要I-485提交时（就是uscis收到时）有身份就行了。
> For purposes of the bars to adjustment, a nonimmigrant only needs to maintain his or her nonimmigrant status until the time he or she properly files an adjustment application with USCIS so long as the nonimmigrant does not engage in any unauthorized employment after filing the adjustment application.
2. 如果I-485被拒了（你的I-485没有什么原因会被拒，但是假设被拒了），unlawful presence从什么时候开始积累？
答案是从I-485被拒那天开始积累。这有两个原因：
首先，违反身份本身不引起unlawful presence开始积累。只有3种情况会引起unlawful presence开始积累：1）留在美国超过I-94上的日期、2）向uscis申请东西并被拒绝，拒绝时被判没有身份、或3）在移民法庭上移民法官判你没有身份。F1的I-94上写的是D/S，没有日期。所以F1离开学校后留在美国多年，就算没有申请I-485或任何其他申请，都不会积累unlawful presence，只要不向uscis申请任何东西，也不被要求上移民法庭的话。看Adjudicator's Field Manual chapter 40.9.2(b)(1)(E)(ii) (在这里第76页）：
> (ii) Nonimmigrants Admitted for Duration of Status (D/S). If USCIS finds a nonimmigrant status violation while adjudicating a request for an immigration benefit, unlawful presence will begin to accrue on the day after the request is denied. If an immigration judge makes a determination of nonimmigrant status violation in exclusion, deportation, or removal proceedings, unlawful presence begins to accrue the day after the immigration judge's order. It must be emphasized that the accrual of unlawful presence neither begins on the date that a status violation occurs, nor on the day on which removal proceedings are initiated.
其次，就算你是I-94上有日期的身份，你I-485 pending期间不积累unlawful presence，就算I-485最终被拒了。看Adjudicator's Field Manual chapter 40.9.2(b)(3)(A) (在这里第85页）：
> Accrual of unlawful presence stops on the date the application is properly filed pursuant to 8 CFR 103 and the regulatory filing requirements governing the particular type of benefit sought.
> Note that, if the application is properly filed according to the regulatory requirements, the applicant will not accrue unlawful presence, even if it is ultimately determined that the applicant was not eligible for the benefit in the first place. The accrual of unlawful presence is tolled until the application is denied.
