The game's save data is contained in two files, both of which need to be moved between computers in order to get everything migrated properly.

These files are so.sol and serial.txt. I have a Mac and a Windows machine, so I'll go ahead and list the location of said files on both platforms (if anyone has any Linux info, feel free to chip in).

On the PC:Edit

serial.txt: Can be found in the game's steam installation folder, something along the lines of

C:\Program Files\Steam\SteamApps\common\the binding of isaac\

so.sol: Can be found over at

%appdata%\Macromedia\Flash Player\#SharedObjects\<some random string>\localhost\

The "random string" bit is some combination of letters and numbers which is impossible to predict. Assuming you've ever run the game, simply search for "so.sol" at "%appdata%\Macromedia\Flash Player#SharedObjects" (you can type this in your run prompt to get there). On my machine I have several so.sol files, but only one is on a path that looks exactly like the one I specified, and that's the one that counts.

On the Mac (Steam Purchase):Edit

serial.txt: Can be found in the game's steam installation folder, something along the lines of

~/Library/Application Support/Steam/SteamApps/common/the binding of isaac/

so.sol: Much like the PC, only over at

~/Library/Preferences/Macromedia/Flash Player/#SharedObjects/(some random string)/localhost/

On the Mac (Non-Steam, e.g. Humble Indie Bundle Purchase):Edit

serial.txt: Located in the same folder as the game.

so.sol: Same as Steam-purchased and PC

~/Library/Preferences/Macromedia/Flash Player/#SharedObjects/4UUE5CSF/localhost/

On Linux:Edit

so.sol: Much like the PC, only over at

~/.macromedia/Flash_Player/#SharedObjects/randomstring/localhost/so.sol

As a final note, you need to move both files, and to launch the game at least once on the target machine to know where they should go.

How serial.txt worksEdit

The file contains the stats (like deaths and collected items) and is used by the game to trigger Secrets which base on specific amounts (like 'Kill all Basement Bosses' or 'Destroy 50 Rocks').

Oddly enough there is a surplus 0 at the start of every chain of related Numbers. (Maybe used as anchor by the game to find the begin of a chain)

<<a very long number>>,

Kind of Serial Number, but without example as its blocked by the spam filter. Changes here and there some numbers, but is overall always the same.

Next are 11 comma-seperated Values

0,true,0,5,720,22,2,13,367,84,2093,

which have the following meaning

1. liststarter_options
2. Preference in the Options which keys are used for shoting tears: true for ArrowKeys, false for ASWD
3. liststarter_statistics
4. Times you killed Mom's Heart/It Lives. (Mom Kills in Stats)
5. Times you destroyed Poop (all Types)
6. Times Blood Donation Machine was used.
7. Times you killed Mom (unknown increase)
8. Times you entered the Arcade
9. Bombs placed. Includes Bombs shot/placed by Dr. Fetus, Mr.Mega and Bob's Rotten Head
10. Times killed; (Deaths in Stats
11. Number of Rocks you (or anyone/anything else) destroyed.

Then a long line of 0 and 1 seperated with Apostroph [" ' "].

0'
1'0'1'1'1'0'1'1'0'1'
1'1'1'1'1'1'1'0'1'1'
1'1'1'1'1'1'1'1'1'1'
1'1'1'1'0'0'1'0'0'1'
1'1'1'1'1'1'1'0'1'0'
1'0'1'1'1'1'0'1'0'1'
1'1'0'1'1'1'1'1'1'1'
1'1'1'1'0'1'1'1'0'1'
1'1'0'1'1'0'1'0'1'1'
1'0'1'0'0'0'1'1'0'1'
0'0'0'1'0'1'0'0'0'0'

1'0'0'0'1'1'1'1'1'1'
1'1'0'1'1'0'0'1'1'1'
0'1'1'1'0'1'1'0'1'1'
1'1'1'1'1'0'0'0'0'1'
0'1'1'1'1'1'1'1'1'1'
1'0'1'0'1'0'1'0'0'0'
0'0'1'0'0'1'0'1'0'1'
1'0'1'0'0'0'0'0'0'0'
1'1'1'1'1'1'1'1,

It lists every Item you collected at least once. For visibility there are linebreaks to seperate it like shown on the Collection Page.

These data values refer to the different values stored in the save of the game.

1: The Sad Onion
2: The Inner Eye
3: Spoon Bender
4: Max's Head
5: My Reflection
6: Number one
7: Blood of the Martyr
8: Brother Bobby
9: Skatole
10: Halo of Flies
11: 1up!
12: Magic Mushroom
13: The Virus
14: Roid Rage
15: <3
16: Raw Liver
17: Skeleton Key
18: A dollar!
19: Boom!
20: Transcendence
21: The Compass
22: Lunch
23: Dinner
24: Dessert
25: Breakfast
26: Rotten Meat
27: Wooden Spoon
28: The Belt
29: Moms Underwear
30: Moms Heels
31: Moms Lipstick
32: Wire Coat hanger!
33: The Bible
34: The Book of Belial
35: The Necronomicon
36: The Poop!
37: Mr. Boom!
38: Tammys Head
39: Moms Bra
40: kamikaze!
41: Moms Pad
42: Bobs Rotten Head
43: Pills here!
44: Teleport!
45: Yum Heart
46: Lucky Foot
47: Doctors Remote
48: Cupids arrow
49: Shoop da Whoop!
50: Steven
51: Pentagram
52: Dr Fetus
53: Magneto
54: Treasure Map
55: Moms Eye
56: Lemon Mishap
57: Distant Admiration
58: Book of shadows
59: Wiggle Worm
60: The Ladder
61: Tarot Card
62: Charm of the vampire
63: The Battery
64: Steam Sale
65: Anarchist Cookbook
66: The Hourglass
67: Sister Maggy
68: Technology
69: Chocolate Milk
70: Growth Hormones
71: Mini Mush
72: Rosary
73: Cube of Meat
74: A Quarter
75: PHD
76: Xray-Vision
77: My little Unicorn
78: Book of Revelations
79: The Mark
80: The Pact
81: Dead Cat
82: Lord of the Pit
83: the Nail
84: We need to go deeper!
85: Deck of Cards
86: Monstros Tooth
87: Lokis Horns
88: Lil Chubby
89: Spider Bite
90: The Small Rock
91: Spelunker Hat
92: Super Bandage
93: The Gamekid
94: Sack of pennies
95: Robo-Baby
96: Little Chad
97: The Book of Sin
98: The Relic
99: Little Gish
100: Little Steve
101: The Halo
102: Moms Bottle of Pills
103: The common cold
104: The Parasite
105: The Dice
106: Mr. Mega
107: The Pinking Shears
108: The Wafer
109: Money = Power
110: Moms Contacts
111: The Bean
112: Guardian Angel
113: Demon Baby
114: Moms Knife
115: Ouija Board
116: 9 Volt
117: Dead Bird
118: Brimstone
119: Blood Bag
120: Odd Mushroom
121: Odd Mushroom
122: Whore of Babylon
123: Monster Manuel
124: Dead Sea Scrolls
125: Bobby - Bomb
126: Razor Blade
127: Forget Me Now
128: Forever alone
129: Bucket of Lard
130: A Pony
131: Bomb Bag
132: A Lump of Coal
133: Guppys Paw
134: Guppys Tail
135: IV Bag
136: Best Friend
137: Remote Detonator
138: Stigmata
139: Moms Purse
140: Bobs Curse
141: Pageant Boy
142: Scapular
143: Speed Ball
144: Bum friend
145: Guppys Head
146: Prayer Card
147: Notched Axe
148: Infestation
149: Ipecac
150: Tough love
151: The Mulligan
152: Technology 2
153: Mutant Spider
154: Chemical peel
155: The Peeper!
156: Habit
157: Bloody Lust
158: Crystal Ball
159: Spirit of the night
160: Crack the Sky
161: Ankh
162: Celtic cross
163: Ghost Baby
164: The Candle
165: Cat-o-nine-tails
166: D20
167: Harlequin baby
168: Epic Fetus
169: Polyphemus
170: Daddy longlegs
171: Spider Butt
172: Sacrificial Dagger
173: Mitre
174: Rainbow Baby
175: Dads Key
176: Stem cells
177: Portable Slot!
178: Holy Water
179: Fate
180: The Black Bean
181: White Pony
182: Sacred Heart
183: Tooth Picks
184: Holy Grail
185: Dead Dove
186: Blood Rights
187: Guppys Hairball
188: Abel
189: SMB Super Fan!
190: Pyro
191: 3 Dollar bill
192: Telepathy for Dummies
193: MEAT!
194: Magic 8 ball
195: Moms coin purse
196: Squeezy
197: Jesus Juice

The next ones

0'1'1'1'1' 1'1'0'1'1'
1'1'1'1'1' 1'0'1'1'0'
1'0'1'0'0' 0'1'0'1'1'
1'0'1'0'1' 0'1'1'1'0'
0'1'1,

are used In-Game to count which Bosses are killed at least once. (For Visibility split up into Groups of 5) The Numbers can be connected to the following bosses:

Bosses encountered in other ways than in the boss room won't be marked as killed, for example, the ones encountered in Sheol/Cathedral before going to Satan/Isaac.

0'44'39'20'19'11'8'5'5'0'0'0,

This ones are used to count the times you killed the Boss of a floor.

1. liststarter_floors
2. Basement / Cellar 1
3. Basement / Cellar 2
4. Caves / Catacombs 1
5. Caves / Catacombs 2
6. The Depths / Necropolis 1
7. The Depths / Necropolis 2
8. The Womb / Utero 1
9. The Womb / Utero 2
10. Sheol
11. Cathedral
12. The Chest

(?)Skiping a boss doesn't seem to increase the value.

1'1'1'1'1'1'1'0'0'0,

I'm not exactly sure, but this line fits for counting which sins are killed. As I did't knew this, the positions of the sins aren't recorded.

73,0

The last one is for counting how many X-Rocks (aka Blue Rock) you have blown up. It is a independent value from the Rock-Counter, but acts similiar. The last number is likely a closing statement.

How so.sol worksEdit

To understand the following text, you should know how the Hexadecimal system works.

How to open the file:

I used Notepad++ as it can display all Control-Characters. I inserted Linebreaks (\r\n) everywhere it fitted, mostly after [STX] (you will see where a line break has to be).

I don't really know, but I've got so far reading the so.sol file:

1.Line == File Header
2.Line == File Name

3.Line gqal == Last used GraphicQualitate HIGH or MEDIUM or LOW

### lines 4-13 == wins, rox, icer, shits, pill ,dde, gams, bomb, deads, rocks

to get the Number, copy all characters between @ and [NUL] and convert it into Hexadecimal and then into decimal.

### lines 5-213 == items (198x)

if collected, the 2nd+3rd [NUL] are ?ð (hex:F03F / dec:61503)

### lines 214-314 == lock (99x)

???

changes from [SOH][SOH][NUL] to [ACK][NUL]

### lines 315-362 == lockor (47x)

???

### lines 363-410 == ulock

???

### lines 411-453 == boss (42x)

Bosses killed at least once

Changes like Items

### lines 454-464 == lcomp (10x)

???

### lines 465-475 == mwin (10x)

Mom Wins

to trigger the Womb-Achivements

changes like items/bosses

### lines 476-479[End]

some Options |}