I'm on F-1 visa , and worked for 18 days on Expired Pre-OPT EAD. Would this cause a problem in the future for OPT STEM applicat?

It could cause a problem as a technical violation, however, the USCIS may forgive minor technical violations in its discretion.

E-3 green card holder. employer/sponsor did not have work in the first year, did not pay wages. will this affect naturalization?

If you are referring to an immigrant petition that was filed under the EB-3 category, the job offer/labor certification must have been bona fide. ...

L1B -> L1A -> GC EB1c

In order to be approved under Section 203(b)(1)(C) you must have worked outside the US for at least one year as a manager or executive. The fact...

I need an Immigration attorney for advice.....I-175 Petition denied by USCIS. What should i do?

You should bring the decision and any related documentation to an immigration attorney for a full consultation.

H1B Transfer gap between two jobs

This should not be a problem, since 10-days is a reasonable transition period between jobs.

According to USCIS, I attained Citizenship through my Mother when she became a citizen. What do i do now?

You file the N-600. Because you automatically "became" a citizen, the name is not changed. You will have to file a petition in State Court to...

I've got H1-B approval this year for FY-2015 CAP. I need to know if I can transfer my H1-B from employer A to B before Oct 1 ?

This should be possible, unless your sponsor was Cap-Exempt and the new employer would not be.

You cannot be commensurated for any services in the US on a B-1.

I'm getting married in June with an US Citizen. What will be my next step to get my green card?

You will either begin the process for obtaining an immigrant visa or filing an application for adjustment of status. Your previous status in the...

Can i cancel my permanent residency status (GR) temporarily?

You should obtain a reentry permit to allow you to leave the US for up to two years without abandoning your status.