The following is taken from the 31 March 2009 Family Tree Magazine Blog:
"Don't let your family history search get sidetracked by these common—but erroneous—genealogical beliefs.
1. You can buy your family crest.Cups, mugs, wall hangings and other family crest doodads are available online everywhere. But “families” don’t have crests—rather, individuals do. Coats of arms must be granted, and to claim the right to arms, you must prove descent through a male line of someone to whom arms were granted Think you qualify?
Get more details on heraldry in our online article.
2. The 1890 census burned to a crisp.Actually, it didn’t—it was waterlogged and lay around until some unknown person authorized its disposal. But some parts survived—
see the full story on the Now What? blog.
3. You can find your whole family history online.If only! Nowadays you can get lots of actual records online, including censuses, passenger lists, military records, digitized books—and on and on. But lots of errors abound in online indexes, transcriptions and family trees, and repositories hold richly detailed, lesser-known records. So at some point, you’ll want or need to log off and go to the library.
When you do, look to our Libraries & Archives category for research tips.
4. Your ancestor was a Cherokee princess or George Washington, or you’re related to John Brown.Lots of families have legends about famous kin, and of course it could be true—but stories tend to get embellished and even made up over time, so research such legends before passing them on as the truth. Regarding the above-mentioned myths: Though you may have Cherokee blood, there weren’t any Cherokee princesses and George Washington can’t be an ancestor because he never had children (Martha did, from her first marriage). Also, not everyone with the same last name is related, even when you go waaaaaaay back in time.
5. The courthouse burned, and all the records are gone.Many a genealogical dream has run smack against a courthouses fire. But the vital records, naturalizations, deeds, wills and other records within weren’t always completely destroyed. Sometimes records survived, or copies had been sent to another office, or the clerk asked citizens for copies of their records, or you can find the same information elsewhere.
See our tips for beating brick walls and contact the county library or state archives, whose staffs may have prepared special helps for genealogists researching around courthouse blazes.
6. Your ancestor's name was changed at Ellis Island.This may be the biggest genealogical myth of all time. Passenger lists were created at the port of departure, and Ellis Island officially checked the names on the list. (One reason why knowing your ancestor’s name in the old country will help you find his passenger record.) Many immigrants changed their own names after arrival in an effort to sound more “American.”
Here are more—actual—ways immigrants’ names were changed. "