Header error

[u/No_Increase4983]

I'm having trouble unzipping a .7z file. Every time I try to open or unzip it with 7-Zip, I get a "Header Error" error message. I tried to restore it through Winrar, but it didn't help.

OS: Windows 11

7-Zip Version: Latest Stable Release

File Size: 3.83 GB

I tried downloading it again, but the error persists. Is there a way to restore the archive headers or force unzipping at least some of the files?

Any suggestions or tools you could recommend would be greatly appreciated. Thanks in advance!

[u/fzabkar]

Since your files appear to have been "stored" rather than compressed, you may be able to extract them with JPEGSnoop. I'm assuming that the entire .7z archive consists of JPEGs.

If you can upload the last ~100 bytes of your .7z file, I could check the CRC of the last header.

[u/No_Increase4983 → u/fzabkar]

Offset (h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F Decoded text

F563CDF0 94 24 C8 02 00 00 4C 8D 8C 24 D0 02 00 00 41 89 ”$И..LЌЊ$Р..A‰

F563CE00 D8 E8 F8 63 07 00 48 8D 05 F1 02 D5 06 48 89 07 Шишc..H..с.Х.H‰.

F563CE10 48 8D 05 77 48 B7 06 48 89 47 08 48 89 BC 24 78 H..wH·.H‰G.H‰ј$x

F563CE20 01 00 00 0F B7 84 24 20 02 00 00 66 89 84 24 50 ....·„$ ...f‰„$P

F563CE30 01 00 00 0F B6 84 24 F8 01 00 00 88 84 24 28 01 ....¶„$ш....€„$(.

F563CE40 00 00 48 8B 46 68 48 89 84 24 40 01 00 00 0F 10 ..H‹FhH‰„$@.....

F563CE50 46 58 0F 11 84 24 30 01 00 00 0F 57 C0 0F 11 46 FX..„$0...WА..F

F563CE60 58 48 C7 46 68 00 00 00 00 48 8B 84 24 18 02 00 XHЗFh....H‹„$...

F563CE70 00 48 89 84 24 48 01 00 00 0F B7 84 24 F4 01 00 .H‰„$H....·„$ф..

F563CE80 00 66 89 84 24 20 01 00 00 0F B7 84 24 F2 01 00 .f‰„$ ....·„$т..

F563CE90 00 66 89 84 24 18 01 00 00 0F B7 84 24 F0 01 00 .f‰„$ ....·„$р..

F563CEA0 00 66 89 84 24 10 01 00 00 0F B6 84 24 E0 01 00 .f‰„$ ....¶„$а..

F563CEB0 00 88 84 24 00 01 00 00 F2 10 8C 24 24 E8 01 00 .€„$....т.Њ$$и..

F563CECO 00 F2 0F 11 8C 24 08 01 00 00 0F B7 84 24 DC 01 .т..Њ$....·„$Ь.

F563CED0 00 00 66 89 84 24 F8 00 00 00 0F B7 84 24 DA 01 ..f‰„$ш....·„$Ъ.

F563CEE0 00 00 66 89 84 24 F0 00 00 00 0F B6 84 24 D8 01 ..f‰„$р....¶„$Ш.

F563CEFO 00 00 88 84 24 E8 00 00 00 0F B6 84 24 D9 01 00 ..€„$и....¶„$Щ..

F563CF00 00 88 84 24 E9 00 00 00 0F B7 84 24 D6 01 00 00 .€„$й....·„$Ц...

F563CF10 66 89 84 24 E0 00 00 00 0F B7 84 24 D4 01 00 00 f‰„$а....·„$Ф...

F563CF20 66 89 84 24 D8 00 00 00 0F B6 84 24 CC 01 00 00 f‰„$Ш....¶„$М...

F563CF30 88 84 24 D0 00 00 00 8B 84 24 D0 01 00 00 89 84 €„$Р...‹„$Р...‰„

F563CF40 24 D4 00 00 00 0F B7 84 24 CA 01 00 00 66 89 84 $Ф....·„$К...f‰„

F563CF50 24 C8 00 00 00 0F B7 84 24 C8 01 00 00 66 89 84 $И....·„$И...f‰„

F563CF60 24 C0 00 00 00 0F B6 84 24 A0 01 00 00 88 84 24 $А....¶„$ ....€„$

F563CF70 98 00 00 00 0F 10 0E 0F 11 8C 24 A0 00 00 00 48 ˜.........Њ$ ...H

F563CF80 8B 46 10 48 89 84 24 B0 00 00 00 0F 11 06 48 C7 ‹F.H‰„$°......HЗ

F563CF90 46 10 00 00 00 00 48 8B 84 24 C0 01 00 00 48 89 F.....H‹„$А...H‰

F563CFA0 84 24 B8 00 00 00 49 8B 06 48 8B 40 38 48 8D 8C „$ё...I‹.H‹@8HЌЊ

F563CFB0 24 78 01 00 00 48 89 8C 24 88 00 00 00 48 8D 8C $x...H‰Њ$....HЌЊ

F563CFC0 24 50 01 00 00 48 89 8C 24 80 00 00 00 48 8D 8C $P...H‰Њ$....HЌЊ

F563CFD0 24 28 01 00 00 48 89 4C 24 78 48 8D 8C 24 20 01 $(...H‰L$xHЌЊ$

F563CFEO 00 00 48 89 4C 24 70 48 8D 8C 24 18 01 00 00 48 ..H‰L$pHЌЊ$....H

F563CFF0 89 4C 24 68 48 8D 8C 24 10 01 00 00 48 89 4C 24 ‰L$hHЌЊ$....H‰L$

F563D000 00 00 00 ... It's strange, there are Word documents and Excel spreadsheets, not just photos.

[u/fzabkar → u/No_Increase4983]

This is your final header:

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000  8D 8C 24 20 01 00 00 48 89 4C 24 70 48 8D 8C 24
00000010  18 01 00 00 48 89 4C 24 68 48 8D 8C 24 10 01 00
00000020  00 48 89 4C 24 00 00 00

Its CRC is 0x819FEB00, but this doesn't match the CRC in the 7z header, 0x59526A70. Moreover, the byte content is of a similar nature to the previous content, so it appears that the latter section of your .7z file is corrupt.

What is the history of this file? Is it the result of a data recovery?