Repair a broken activity file

FIT is a binary format, not XML, and that difference matters a lot when a file won't open. A GPX or TCX file corrupted only at the very start can often be recovered by finding the real opening tag further in and discarding the damaged prefix, because the rest of the text is still legible. FIT doesn't have that safety net: it's a sequence of binary-encoded messages with no readable tags to search for, so a handful of corrupted bytes near the start tends to make the whole thing unparseable, with no reliable point to splice from. If that's genuinely what happened to your file — corruption in the binary structure itself — no tool, including FitFileHub's, can safely reconstruct the missing bytes. In practice, though, a lot of files reported as "won't open" aren't corrupted at the container level at all — some app refused to import them over a content problem further in: missing timestamps on some points, timestamps running backward, duplicate records, or a segment implying an impossible speed. Those are exactly the defects FitFileHub's repair tool checks for, and unlike header corruption, all of them apply to FIT files the same as GPX or TCX. Running your file through the tool first tells you which situation you're actually in — it reports every defect found before fixing anything, so if it comes back clean structurally, the FIT container itself parses fine and the problem lies elsewhere, most likely the platform you tried to upload to. The check runs entirely in your browser — the file never leaves your device just to find out what's wrong with it. Free for files up to 25 MB, three at a time.