If a user receives a "CRC failed - file locked" status after transferring a file with the Web Transfer Client, examine your Event Rules.
The integrity check (XCRC) occurs when the browser client finishes the upload with a request to EFT Server to verify the integrity of the file. If your "File Uploaded" Event Rule has a rename or move Action, EFT Server cannot perform the integrity check, because the file is no longer in the location where it was uploaded or was renamed.
You can use the "Verified Upload Succeeded" Event Rule to handle the post-upload processing when files are uploaded using the Web Transfer Client (WTC). This means that WTC will be able to verify integrity, after which the Event Rule triggers.
If you allow uploads with other clients (not just WTC), then you need a separate "File Uploaded" Rule; however, on that Event Rule, add the "If Using Web Transfer Client Equals No" Condition so that the Event Rule does NOT trigger for WTC uploads.
(Refer to Event Rules for details of defining Event Rules and using Conditions and Actions.)