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CAB Inspector: View and Extract Windows Cabinet (.cab) Files Online
Pick a .cab file and CAB Inspector reads the Microsoft Cabinet structure in your browser. The header panel shows the format version, the declared cabinet size next to the real size, the set ID, the cabinet number in a set, reserved areas and the names of any previous or next cabinet. The folder table lists each folder's compression method (none, MSZIP, Quantum or LZX with its window bits), first data block offset, block count, declared output and per-block checksum results. The file table gives the display name, the exact stored name, a flat sanitized save name, size, folder, offset, DOS modification time, attributes and name encoding, and flags names with path traversal, absolute paths, drive letters, NUL bytes or duplicates. Enter a file number to extract it from an uncompressed folder or a single-block MSZIP folder; UTF-8 text is previewed and, when the preview is complete, can be saved under the sanitized name. The full file list can be downloaded as a tab-separated listing.
File types: .cabProcessing: This browser
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✓ Stays on this deviceMaximum size: 100 MB
How to use CAB Inspector: View and Extract Windows Cabinet (.cab) Files Online
Let it read the file
The file is read and parsed in this browser — nothing is uploaded.
Check the result
Look over what came back, then copy it, download it, or move on.
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Common questions
How do I open a CAB file online and see the files inside it?
Choose the .cab file and the page lists every folder and file it contains, with sizes, modification dates, attributes and each folder's compression method. Above the tables, the header panel compares the declared cabinet size with the real size and shows any link to a previous or next cabinet in a set.
How do I extract one file from a CAB file in the browser?
Type the number from the first column of the file table into the extract field and only that file is returned to you; to get it, the tool decompresses the file's whole folder stream in memory and cuts the entry out, which works when that folder is uncompressed or a single-block MSZIP folder. The result panel shows its size and flat save name; UTF-8 text is previewed and, when the preview is complete and has no byte-order mark, offered for saving.
Is my CAB file uploaded to a server when I inspect it here?
No. The cabinet is read into your browser's memory and parsed on your own device, and neither the cabinet nor any extracted file is sent to a server or kept in browser storage. Closing or reloading the tab discards everything.
How do I open a CAB file on a Mac without Windows?
macOS has no built-in CAB support, but opening the .cab here in Safari, Chrome or Firefox lists its full contents and extracts stored or single-block MSZIP entries. Driver and update cabinets often use LZX, which this page lists but cannot decompress; for those you need a desktop archive utility with an LZX decoder.
Can I view a CAB file on Windows 11 without running expand.exe?
Yes. File Explorer on Windows 11 already browses many .cab files, and this page adds what Explorer does not show: compression method per folder, per-block checksum results, unsafe path warnings and multi-cabinet continuation. Keep using Explorer or expand.exe when you need LZX content written to disk.
Why does my CAB file show unsupported compression method for LZX or Quantum folders?
LZX and Quantum folders are read for their structure, but this tool has no decompressor for those two methods, so their files are listed with extraction disabled and the reason shown in text. Names, sizes, dates and checksum results for those files are still reported accurately.
Why can't I extract a file from an MSZIP CAB folder with several data blocks?
Each MSZIP block after the first is compressed against the previous 32 KB of output, and the browser's built-in deflate decoder cannot be primed with that history, so such folders are refused instead of returning damaged bytes. Because one block holds at most 32 KB of uncompressed data, this affects most MSZIP folders larger than that.
What does a CAB checksum mismatch or bad signature error mean?
A bad signature means the file does not start with the four bytes MSCF, so it is not a Microsoft Cabinet, often a renamed file or a broken download. A checksum mismatch means a data block's stored checksum disagrees with its bytes, which indicates corruption; the files stay listed, but extraction from that folder is refused.
Why are some files in my CAB file marked incomplete in this cabinet?
Those files start in a previous cabinet or continue into the next one of a multi-disk set, so this .cab holds only part of their data. The header panel names the previous and next cabinet files, but the tool does not join cabinets, so these files cannot be extracted here.
What is the largest CAB file this viewer can open, and how many files can it list?
Cabinets up to 100 MB (104,857,600 bytes) are accepted, and up to 20,000 folders and 20,000 files are listed, with a warning when a cabinet declares more. A folder is extracted only if its declared output is at most 64 MB, and text previews and the downloadable listing stop at 200,000 characters.
Is a CAB file safe if the inspector shows no warnings and every checksum passes?
No. Passing checksums and a clean listing only show the cabinet is structurally intact; they say nothing about whether its contents are harmless. No Authenticode signature is read and nothing is scanned for malware, so verify the publisher with Windows signature tools and a security scanner before running anything from it.
Can I extract a CAB file without installing software, and what is the difference between CAB and ZIP?
Yes for uncompressed and single-block MSZIP folders: open the .cab here and extract entries one at a time by number, with no installation or account. Unlike ZIP, which compresses each file separately, CAB compresses all files of a folder as one stream, which packs small files tighter but makes single-file extraction depend on the whole folder.