FastCopyCRC errors while copying: 5 causes and the matching fix
11. USB cable or port (external drives)
A worn USB cable is the single most common cause with external enclosures. Swap the cable, then try a different port — ideally a rear motherboard port rather than a front-panel or hub port.
22. Bad sectors on the source or destination
Run chkdsk /r (Windows) on the failing drive, or check SMART values with CrystalDiskInfo. Pending/reallocated sector counts climbing means the drive itself is failing — copy what you can off it immediately, then replace it.
33. Unstable RAM (rare, but real)
If errors appear across different drives and cables, test memory with MemTest86. FastCopy reads into RAM before writing, so faulty memory can corrupt either direction.
44. Network paths and unreliable links
Copying from a NAS or flaky Wi-Fi introduces its own error paths. Try a wired connection, or copy to a local disk first, verify, then move the data onward.
55. Retry with verification enabled
After fixing the hardware cause, re-copy the affected files with Verify enabled in the settings. FastCopy will hash source and destination and report any remaining mismatch explicitly.
Frequently asked
QDoes a CRC error mean my file is now corrupt?
FastCopy aborts or flags the affected file — the unflagged files are fine. Delete the flagged destination file and re-copy it after fixing the cause.
QCan I tell FastCopy to ignore errors and continue?
Yes — in the prologue/option settings you can choose to ignore errors and continue, but only do this for disposable data. For anything important, fix the cause first.
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