I am quoting words from INS web site:

Quote
if you have accrued more than 180 days of unlawful presence and then travel abroad, you will be barred from adjustment of status for either three years or 10 years
Unquote

my question is
if someone overstays for more than 180 days and stays in US until his COS or interview for GC comes then what will happen?

your cooments will be appreciated

kim

If you overstayed but you filed for an AOS based on marriage for example, that won't apply to you.

The bans are IF you leave the country. If you need to leave the country, you could try for an AP aka travel document but it's not a guarantee that you will be allowed back in. If you overstayed, they may ban you.

If you have overstayed, the best thing is to not leave until you have your green card.

Hope it helps.

I stayed beyond 180 days and did an aos based on marriage......the advice I was given was NOT to leave. Even if you apply for AP they can still refuse you entry on your return.

I would suggest you stick it out and wait untill you get your GC.