This is like the thread in Official songs, it'll take way too much time to do this in a thread per song.
NB: these fixes are only for songs that, once downloaded and unpacked, end up in the 'Community' folder. Aka, they are all for older songs, before songs could be downloaded individually.
In the post I just list the songs and what is wrong with them on a not-super-technical level. See the linked two diff files for my proposed solutions. Numbers refer to beats, not line numbers.
4EverfreeBrony - Chant of Mirth/notes.txt
* The note starting at 2110 overlaps with the one starting at 2097
4EverfreeBrony - Chant of Mirth/notes.txt
* duplicate #LANGUAGE tag
AcousticBrony, MandoPony - I'll Fly Higher/notes.txt
* linebreak at 54 interferes with previous note
* linebreak at 156 interferes with previous note
* linebreak at 382 interferes with previous note
Andrew Huang - PFUDOR/notes.txt
* zero-length note plus extra linebreak at 568
* linebreak at 1131 intereferes with previous note
AwkwardMarina - Anthropology/instrumental.txt
* duplicate #UPDATED tag
Black Gryph0n, Michelle Creber - Beat It/notes.txt
* invalid #UPDATED separator (! instead of :)
BlackGryph0n, Baasik, Michelle Creber - Getting Stronger/notes.txt
* overlapping notes+linebreak around 244-250
BronyFX - Discord's Lament/notes.txt
* duplicate #YEAR tag
DaWillstanator feat BriLizyT - Lullaby For A Princess/duet-instrumental.txt
and
DaWillstanator feat BriLizyT - Lullaby For A Princess/duet.txt
and
DaWillstanator feat BriLizyT - Lullaby For A Princess/instrumental.txt
and
DaWillstanator feat BriLizyT - Lullaby For A Princess/tia.txt
* linebreak at 6112 interferes with previous note
DaWillstanator feat BriLizyT - Lullaby For A Princess/luna.txt
* multiple #GENRE tags
F3nning - Fluttershy's Gala/notes.txt
* linebreak at 790 interferes with previous note
Feather - Mad Mares/notes.txt
* linebreak at 3130 interferes with previous note
FiW - Gypsy Bard - Extended/instrumental.txt
and
FiW - Gypsy Bard - Extended/notes.txt
* linebreak+note at 326 interfere with note previous note (the one starting at 324)
Filly Funtasia - From Now Until Forever/notes.txt
* linebreak at 722 interferes with previous note
Flapplejack/notes.txt
* linebreak at 33 interferes with previous note
Forest Rain - Memory Lane/notes.txt
* duplicate #EDITION tag
* linebreak at 1571 interferes with previous note
* overlapping notes (and linebreak) around 1781-1795
* linebreak at 2411 interferes with previous note
* linebreak at 2982 interferes with previous note
* linebreak at 3342 interferes with previous note
* linebreak at 4075 interferes with previous note
* linebreak at 4324 interferes with previous note
* linebreak at 5098 interferes with previous note
Forest Rain - Trixie/instrumental.txt
and
Forest Rain - Trixie/notes.txt
* multiple #UPDATED tags
Kenny9807 - Apples to the Core (Rock Version)/notes.txt
* linebreak at 125 interferes with previous note
* linebreak at 450 interferes with next note
* linebreak at 689 interferes with previous note
* linebreak at 1729 interferes with next note
Mandopony, Eilemonty - Picture Perfect Pony/notes.txt
* illegal instruction at 1375 (f instead of F)
* overlapping notes (and linebreak) around 1430-1436
* overlapping notes (and linebreak) around 2019-2024
Meelz - Twilight Sparkle, You're My Reason to Live/instrumental.txt
and
Meelz - Twilight Sparkle, You're My Reason to Live/notes.txt
* multiple #UPDATED tags
Metajoker feat. Fluttershyay - Universe/notes.txt
* linebreak at 2145 interferes with previous note
Ponime - Luna Genesis Evangelion/instrumental.txt
and
Ponime - Luna Genesis Evangelion/notes.txt
* linebreak at 840 interferes with next note
Ponyphonic - Lullaby for a Princess/instrumental.txt
and
Ponyphonic - Lullaby for a Princess/notes.txt
* linebreak at 128 interferes with previous note
Ponyphonic - The Moon Rises/notes.txt
* duplicate #LANGUAGE tags
PrinceWhateverer - Frailty/notes.txt
* duplicate #LANGUAGE tags
Sand Josieph (ft. Lanovran & SiminaCindy) - Daddy Discord/duet-instrumental.txt
and
Sand Josieph (ft. Lanovran & SiminaCindy) - Daddy Discord/duet.txt
* zero-length note at 2420 (did not look into how the other versions don't have this error, maybe they solve it in a better way than I did)
Silver Note - Chasing Marks/instrumental.txt
and
Silver Note - Chasing Marks/notes.txt
* multiple #GENRE tags
Tara Strong - Take My Hand/notes.txt
* linebreak at 1777 interferes with previous note
Tarby - Kaos Rizing/notes.txt
* linebreak at 863 interferes with previous note
The Count of Monte Cristo - I Will Be There/duet.txt
* linebreak at 1420 interferes with previous note
The L-Train - Fall of an Empire/12-ch8-duet.txt
* mupltiple #START tags (as fix I looked at what the other version used)
The Living Tombstone feat. Dasha - Good Girl/instrumental.txt
and
The Living Tombstone feat. Dasha - Good Girl/notes.txt
* linebreak at 577 interferes with previous note
* linebreak at 849 interferes with previous note
* linebreak at 1635 interferes with previous note
UnderPony - Aloe Aloe/notes.txt
* duplicate #LANGUAGE tag
Voodoopony ft iBringDaLulz - Dreams of an Earth Pony/notes.txt
* notes starting at 2530 and 2532 overlap
* notes starting at 4750 and 4754 overlap
WoodenToaster, The Living Tombstone - Love me Cheerilee/instrumental.txt
* between notes starting at 481 and 522, there is a linebreak for 5012
zatslol - Alicornication/notes.txt
* duplicate #LANGUAGE tags
H8_Seed - Heartstrings/notes.txt
* unnecessary linebreak at 1810
Nyan/notes.txt
* unnecessary linebreak at 1529
SimGretina, MEMJ - Dear Luna/notes.txt
* unnecessary linebreak at 3842
links to fixes:
Fixes 1 (general fixes):
https://drive.google.com/open?id=1H00itduVSTSw7qnv4SwHTEWYXTj5PMUy
Fixes 2 (unnessecary linebreaks):
https://drive.google.com/open?id=1S7qxNIafoUZtPjTusER3pmuViRDyaIL1