start of central directory not found; zipfile corrupt.

[Ashton-W]

I followed the install instructions but when I try and unzip this IPA file I found I get this error.

Archive:  pre-thinned1234.thinned.signed.dpkg.ipa
error [pre-thinned1234.thinned.signed.dpkg.ipa]:  start of central directory not found;
  zipfile corrupt.
  (please check that you have transferred or created the zipfile in the
  appropriate BINARY mode and that you have compiled UnZip properly)

Any idea what I've done wrong? I'm on macOS 10.13.6 (no good reason, just using an old mac)

[krin-san]

I have a similar issue. Unzipping dpkg.ipa from AppStore gives this result:

Archive:  pre-thinned3407173400144207043.thinned.signed.dpkg.ipa
error:  expected central file header signature not found (file #5).
  (please check that you have transferred or created the zipfile in the
  appropriate BINARY mode and that you have compiled UnZip properly)
file #1:  bad zipfile offset (local header sig):  0
file #2:  bad zipfile offset (local header sig):  55
warning:  filename too long--truncating.
META-INF/com.apple.FixedZipMetadata.bin:  mismatching "local" filename (??a?S8w?+???0דj????u?|?f+?),
         continuing with "central" filename version
dst/META-INF/com.apple.FixedZipMetadata.bin:  unknown compression method
file #4:  bad zipfile offset (local header sig):  612

and when unzipping beta.ipa from TestFlight:

Archive:  pre-thinned16421275706335294794.thinned.signed.beta.ipa
error [pre-thinned16421275706335294794.thinned.signed.beta.ipa]:  start of central directory not found;
  zipfile corrupt.
  (please check that you have transferred or created the zipfile in the
  appropriate BINARY mode and that you have compiled UnZip properly)

[0x3c3e]

Same issue for app downloaded from App Store.

[laoyur]

same here, seems like apple encrypt the ipa?

[coolkidhai]

same here, seems like apple encrypt the ipa?

it seems changed after ios12.

[fsevenm]

Same, is there any updates on this.

   skipping: META-INF/com.apple.ZipMetadata.plist  `LZFSE' method not supported
error:  expected central file header signature not found (file #3).
  (please check that you have transferred or created the zipfile in the
  appropriate BINARY mode and that you have compiled UnZip properly)
file #1:  bad zipfile offset (local header sig):  0
META-INF/com.ap?^G??^]?t???^]5"t??????u?{^U:  mismatching "local" filename (z?a?2?%!??v?rC=),
         continuing with "central" filename version
META-INF/com.ap?^G??^]?t???^]5"t??????u?{^U:  ucsize 27133910 <> csize 2723216212 for STORED entry
         continuing with "compressed" size value
 extracting: META-INF/com.ap????t??5"t??????u?{   bad CRC 8b70fe8f  (should be a05e69b0)

I can see this at the beginning of the binary.

0000000000 a0 a7 05 58 a1 cd 9a a6 0d d1 6e 6e ee 4b db 67   ...X......nn.K.g
0000000010 f4 46 33 e7 b2 53 54 4d 04 f2 5e 90 bf 05 43 1a   .F3..STM..^...C.
0000000020 58 03 50 4f 30 95 46 ab a3 c9 42 fa 13 49 9f c9   X.PO0.F...B..I..
0000000030 03 d5 c1 d1 c9 37 8a 68 2e d6 a6 59 e7 04 42 42   .....7.h...Y..BB
0000000040 45 c4 e8 78 57 c6 b6 d0 ef fd 86 b3 f4 1a 31 8f   E..xW.........1.
0000000050 be 88 ff 04 76 bc c0 92 de b9 b7 a9 16 a9 2a ba   ....v.........*.
0000000060 58 4b 60 9b a1 19 80 33 6a fb 75 b0 8f e4 8c 20   XK`....3j.u.... 
0000000070 61 74 61 2e 70 6c 69 73 74 55 58 0c 00 cb 96 25   ata.plistUX....%
0000000080 64 cb 96 25 64 f5 01 f5 01 62 76 78 6e 79 01 00   d..%d....bvxny..
0000000090 00 5d 01 00 00 e0 32 62 70 6c 69 73 74 30 30 d7   .]....2bplist00.
00000000a0 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 5f 10   .............._.
00000000b0 11 53 74 61 6e 64 61 72 64 46 69 6c 65 50 65 72   .StandardFilePer
00000000c0 6d 73 57 56 65 72 73 69 6f 6e 5b 52 65 63 6f 72   msWVersion[Recor
00000000d0 64 43 6f 75 6e 74 5f 10 16 28 28 e9 44 69 72 65   dCount_..((.Dire
00000000e0 63 74 6f 72 79 10 2d 00 19 e4 43 72 65 61 00 10   ctory.-...Crea..
00000000f0 e8 54 6f 6f 6c 43 6f 6d 6d 00 26 e7 4c 69 6e 65   .ToolComm.&.Line
0000000100 5f 10 0f 38 19 f1 e4 55 55 49 44 00 2b e0 08 54   _..8...UUID.+..T
0000000110 6f 74 61 6c 55 6e 63 6f 6d 70 72 65 73 73 65 64   otalUncompressed
0000000120 42 79 74 65 73 13 ff 10 01 e0 00 81 a4 10 02 10   Bytes...........
0000000130 5f 11 41 ed 5f 10 60 22 5a 69 70 08 38 e5 22 20   _.A._.`"Zip.8." 
0000000140 22 2d 63 00 05 e8 31 30 34 38 35 37 36 30 08 10   "-c...10485760..
0000000150 48 05 73 08 04 40 05 6d e5 6c 7a 66 73 65 00 08   H.s..@.m.lzfse..
0000000160 c0 99 65 78 74 e0 00 71 61 65 6b 72 61 67 6c 7a   ..ext..qaekraglz
0000000170 73 6b 68 76 6d 74 75 08 21 e0 50 69 6e 35 39 38   skhvmtu.!.Pin598
0000000180 33 30 31 34 39 38 36 35 38 35 33 37 31 34 30 22   301498658537140"
0000000190 5f 10 24 44 46 30 31 31 37 43 30 2d 37 46 38 35   _.$DF0117C0-7F85
00000001a0 2d 33 36 46 37 2d 38 32 32 46 2d 45 34 32 44 46   -36F7-822F-E42DF
00000001b0 38 30 34 34 42 32 39 12 01 30 3f b8 00 08 00 17   8044B29..0?.....
00000001c0 00 2b 00 33 00 3f 00 58 00 71 00 83 00 9c 00 a5   .+.3.?.X.q......

[jpstotz]

Yes, Apple partially encrypts IPA files. If I remember correctly just one block (16 byte?) about every 512 byte.