He promised he would let me hear it, but we learned that although the song was listed on a tape box it was spliced out by Harry. Apparently he did that when he was unhappy with something he had recorded.
-- Margo Guryan (2017) 
We learned from someone at RCA who was compiling a Nilsson package that "Think of Rain" was listed on a tape box, but razor-cut out. (Harry apparently did that when he didn’t like a performance.) Harry told me that he had tried recording the song many different ways - fast, slow, hard, soft - but nothing worked. He said he’d let me hear it, but never did. So it was never released, I never heard it, and the public will never hear it. Alas!
-- Margo Guryan (2012) 
I already had a telephone friendship with Harry Nilsson. He recorded "Think of Rain" but didn't like the way it came out. It was never released. And, though he promised, I never heard it. He gave it to Judy Carne who performed it on "Laugh-In."
-- Margo Guryan (2015) 
Asked in 2018 about her songwriting and arranging process, Guryan mentions Harry:
The "arrangement" was usually part of the song as I was writing it. I didn’t write a song and then attempt to arrange it. That never worked for me, although it worked beautifully for others. George Tipton, who arranged Harry Nilsson’s "Without Her" is a case in point. It was the first song written by Harry that I heard. The cello line that Tipton employed is magnificent! Though I admire the contributions of many brilliant arrangers, my arrangements were always written into my songs.
-- Margo Guryan (2018) 
-  writingonmusic.com, Fiona McQuarrie (2017-03-06) " Heartaches and Raindrops: Margo Guryan’s "Think of Rain"" (https:/
/) writingonmusic. com/ 2017/ 03/ 06/ heartaches- and- raindrops- margo- guryans- think- of- rain/
-  " Margo Guryan :: The AD Interview" Aquarium Drunkard (2012-09-27) (https:/
/) aquariumdrunkard. com/ 2012/ 09/ 27/ margo- guryan- the- ad- interview/
-  Salon.com, Benjamin Wheelock (2015-08-12) "You Must Hear This! Margo Guryan's "Sunday Morning"" (https:/
/) www. salon. com/ 2015/ 08/ 12/ you_must_hear_this_margo_guryans_sunday_morning/
-  It’s Psychedelic Baby, Klemen Breznikar (2018-03-18) "Margo Guryan - Interview" (https:/
/) www. psychedelicbabymag. com/ 2018/ 03/ margo- guryan- interview. html