If you are using a Linux script (like geteltorito) to extract the ISO and write it to a USB stick, it will fail with this error.
The Solution: You do not need to extract the ISO. Lenovo provides a USB package specifically for this purpose.
To understand the error, we must dissect the acronym SAK. Depending on your context, SAK generally refers to: sak decompression failed
Decompression is the process of reconstructing original data from a compressed format (like ZIP, GZ, or custom LZSS). When the system reports that decompression failed for a SAK, it means the algorithm cannot reconstruct the original data because the input stream is corrupted, incomplete, or tampered with.
Decompression often requires 2-3x the compressed file size in temporary space. If your RAM is full or your /tmp directory (Linux) or %TEMP% (Windows) is out of space, the decompressor cannot write the reconstructed data. If you are using a Linux script (like
If the file is partially corrupted but contains irreplaceable data (e.g., a custom game mod you cannot re-download), you can attempt raw recovery.
User: Opened a 10-year-old .sak backup from a dead NAS drive.
Error: "SAK decompression failed" instantly.
Solution: The drive had bad sectors exactly on the header block. Using GNU ddrescue to clone the drive sector-by-sector recovered the missing header bytes, allowing the decompressor to read the file. To understand the error, we must dissect the acronym SAK
A high-energy neutron flipped bit 47 of a 64-bit word in the decompression buffer, corrupting an in-memory length header after the cyclic redundancy check (CRC) of the compressed stream had passed, but before final expansion. The SAK format does not have end-to-end integrity after decompression; only pre-decompress checksum.
Sometimes, the error has nothing to do with SAK. A generic decompression library (like 7-Zip’s internal DLLs) might output a memory address or buffer error that the front-end program mislabels as "SAK." This is rare, but it means the issue could be system RAM or a faulty hard drive.
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