I hope you find the following information useful - more will be added as I find it.

One thing shows the religion of the Seventh Day Adventists to be false and that is their holding of the seventh day (Saturday - the Sabbath) as a special day and that if any man does not hold to this old commandment then they are anti Christian.

God's Word!

Col 2:16 Let no man therefore judge you in meat, or in drink, or IN RESPECT of an holyday, or of the new moon, or of the sabbath days:

And in accordance with the keeping of the commandments as a means of salvation...

Gal 3:10 For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.

Salvation is not by the law or by the works of man.

Ga 2:21 I do not frustrate the grace of God: for if righteousness come BY THE LAW, then Christ is dead in vain.
Ga 3:11 But that no man is justified BY THE LAW in the sight of God, it is evident: for, The just shall live by faith.
Ga 3:21 Is the law then against the promises of God? God forbid: for if there had been a law given which could have given life, verily righteousness should have been BY THE LAW.
Ga 5:4 Christ is become of no effect unto you, whosoever of you are justified BY THE LAW; ye are fallen from grace.

Eph 2:8 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Eph 2:9 Not of works, lest any man should boast.

Again thanks to Faith Defenders for this information

FACT SHEET ON ELLEN G. WHITE
by Dr. Robert A. Morey
There is only one fundamental issue between Evangelicals and Seventh-day Adventists: Was Ellen G. White a prophetess of God? She was either whom she claimed to be, a liar, or a nut case. There are no other logical options.

I. Her Claims:
"God was speaking through clay. In these letters which I write, in the testimonies I bear, I am presenting to you that which the Lord has presented to me. I do not write an article in the paper expressing merely my own ideas. They are what God has opened before me in vision--the precious rays of light shining from the throne." E.G. WHITE TESTIMONIES, vol. 3, p. 63.

"When I send you a testimony of warning and reproof, many of you declare it to be merely the opinion of Sister White. You have thereby insulted the Spirit of God." E.G. WHITE TESTIMONIES, Vol. 5, p. 66l.

"Those who are reproved by the Spirit of God should not rise up against the humble instrument. It is God and not an erring mortal, who has spoken to save them from ruin." TESTIMONY FOR THE CHURCH, Vol. 3, p. 257.

"Seventh Day Adventists hold that Ellen G. White performed the work of a true prophet during the seventy years of her public ministry. As Samuel was a prophet, as Jeremiah was a prophet, as John the Baptist, so we believe that Mrs. White was a prophet to the church of Christ today." THE ADVENT REVIEW & HERALD (l0/4/l928)

II. The Evidence: What of White's Prophecies? Did she predict the Second Coming of Christ? Yes she did!
l843 "I have seen that the l843 chart was directed by the hand of the Lord and that it should not be altered, that the figures were as he wanted them." Early Writings, p. 64, l882 ed.

l844 "We heard the voice of God like many waters, which gave us the day and hour of Jesus' coming." A Word To The Little Flock, p. l4, l847 ed.

l845 "It is well known that many were expecting the Lord to come at the 7th month, l845. That Christ would then come we firmly believed. A few days before the time past...Ellen was with the band at Carver, Mass., where she saw in vision, that we should be disappointed." A Word To The Little Flock, p.22, l847 ed.

l849 "Now time is almost finished and what we have been 6 years learning they will have to learn in months." Early Writings, p. 57.

l856 "I was shown the company present at the conference. Said the angel: 'Some food for worms, some subjects of the seven last plagues, some will be alive and remain upon the earth to be translated at the coming of Jesus." Testimonies For The Church, vol. I, pp. l3l-l32.

l862 "The system of slavery, which has ruined our nation, is left to live and stir up another rebellion." Early Writings, p. 256.

Since White's predictions of the return of Christ did not come true, we must conclude on the basis of Deut. 18:21-23 that she was a false prophet.

III. What About White's Visions?
The biblical and historical material which White claimed to receive by way of visions were actually stolen from dozens of books. (See: Walter Rea, The White Lie, M&R Pub., 1982, Box 2056, Turlock, Ca. 9538l). The health and nutrition visions were also stolen from medical books of that period. (See: Ronald Numbers, Prophetess of Health, Harper & Row, N.Y., olen from medical books of that period. (See: Ronald Numbers, Prophetess of Health, Harper & Row, N.Y., 1976).

Conclusion The only conclusion possible is that Ellen G. White was not only a dishonest woman who plagiarized the works of others, but she was also a false prophet.