Archive error messages tend to be technical and unhelpful by default — a leftover from formats designed decades before phones existed. Here's what the common ones actually mean and the fix that applies to each, roughly in order of how often they come up.

"CRC failed" or "checksum mismatch"

Every archive format stores a small checksum for its contents so the extractor can confirm the data wasn't altered or corrupted. This error means the checksum didn't match, almost always because the download was interrupted or the file was corrupted in transit. Retrying the extraction won't help, since the fault is in the file, not the extraction process. Re-download the archive from its original source; if the problem repeats, the file may be broken at the source and worth reporting to whoever shared it.

"Unsupported format" or "not a valid archive"

This usually means one of three things:

  • The file extension doesn't match its actual contents (a file renamed to .zip that's really something else).
  • Your archive app is outdated and doesn't yet support a newer variant of the format, such as RAR5.
  • The file didn't finish downloading and only a partial header exists.

Updating your archive app resolves the second case; re-downloading resolves the third. For the first case, check where the file came from.

"Wrong password" on a password you're sure is right

Passwords for encrypted archives are typically case-sensitive and don't tolerate extra spaces. If you copied the password from a text message or email, check for an accidental trailing space, a smart-quote character substituted for a straight one, or autocapitalization changing the first letter. Retyping the password manually, rather than pasting it, catches most of these issues.

Extraction starts, then stops partway with no clear error

This is most often a storage space problem. Archives can expand well beyond their compressed size — a 50 MB ZIP of text files might extract to several hundred megabytes. Check your device's available storage before extracting anything you suspect is large, and clear space if needed rather than assuming the app has hung.

"Permission denied" when extracting to a specific folder

On Android 11 and later, apps need explicit "All files access" permission to write outside their own sandboxed folder. If your archive app hasn't been granted this, extraction to system folders or other apps' folders will fail silently or with a permission error. Check Settings → Apps → [your archive app] → Permissions, and enable file access if it's currently restricted.

Multi-part archive fails on the last part

If a split archive (.part1.rar, .part2.rar, and so on) extracts most of the way and then fails, check that every part downloaded completely and that none were renamed. Cloud storage services sometimes append "(1)" to a duplicate filename automatically, which breaks the sequence the extractor expects.

General rule: if an error mentions the data itself (CRC, checksum, corrupt), re-download the file. If it mentions permissions or format support, check your app's settings or update it. Retrying the same extraction rarely fixes either kind.

Still stuck on a RAR file specifically? Our RAR extraction guide covers multi-part archives and RAR5 in more detail.