Batch Corrupted CAJ File Screening Tool

Scans CAJ files in a specified directory, automatically identifies corrupted files, and copies or moves them to a save directory as needed, with support for recursive subdirectories and duplicate-name handling.

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Tool Usage

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A desktop version is available with more powerful, stable features. Open desktop version

Instructions

Software Usage Instructions

Select items to process: Enter or drag the CAJ files or folders to be scanned into the "To Process" input box. You can also click the "Browse Files" or "Browse Folders" button to add them. Multiple paths can be selected at the same time, separated by English semicolons ";".
Traverse subdirectories: When checked, all CAJ files in all levels of directories under the selected folder will be scanned recursively; when unchecked, only the top-level directory will be scanned.
Set save directory: Select the save directory for damaged files in the "Save to" input box. Manual input, clicking "Browse", or dragging in a path are supported.
Keep original path structure: Available only when "Traverse subdirectories" is checked. When checked, damaged files saved to the target directory will replicate the original directory hierarchy.
Select operation mode:
- Copy: Keep the original file and copy the damaged CAJ to the save directory
- Move: Cut the damaged CAJ from its original location to the save directory
Set duplicate-name strategy: When a file with the same name already exists in the target directory, you can choose "Auto rename" (append a number to the file name), "Skip", or "Overwrite".
Start processing: Click the "Start" button to begin scanning. The progress bar and log area display the processing progress and list of damaged files in real time. You can click "Stop" at any time to interrupt the process.
View results: After processing is complete, the log will output the total number of files, the number of damaged files, and the number processed. You can go to the save directory to view the filtered damaged CAJ files.

FAQ

A: The tool uses a multi-check detection mechanism, including checking whether the file exists and is readable, whether the file size is too small (less than 256 bytes), whether the file header matches known format signatures such as CAJ/HN/KDH/PDF, and reading the end of the file to determine whether it has been truncated (an all-zero tail usually indicates an incomplete file). It combines these results to identify damaged files that cannot be opened.

A: Copy keeps the damaged file in its original location and only creates an additional copy in the save directory. This is a safer option if you want to inspect the files first before deciding whether to delete them. Move directly cuts the file from the original directory to the save directory, which is suitable when you have already decided to centrally remove damaged files from the original document library. It is recommended to choose "Copy" for first-time use.

A: When checked, corrupted files saved to the target directory will replicate the original folder hierarchy. For example, if the original file is located at D:\文献\2023\物理\xxx.caj and the save directory is E:\损坏\, it will be saved as E:\损坏\2023\物理\xxx.caj, making it easier to trace the file source later. This option is available only when "Traverse subdirectories" is checked.

A: No. The tool uses streaming processing and background threads. Files are read and verified one by one as needed, and all file paths are not loaded into memory at once; the log window also keeps only the latest 200 records, making it suitable for scanning large-scale literature libraries. You can click "Stop" at any time during processing to interrupt safely.

A: When a CAJ file with the same name already exists in the target directory, the tool appends an incremental "_number" suffix to the file name. For example, if paper.caj already exists, the new file will be saved as paper_1.caj; if there is another conflict, it will continue as paper_2.caj, ensuring that no existing files are overwritten.

A: In rare cases, some encrypted versions or less common variants of CAJ files may be misidentified because their file headers are not in the known list. It is recommended to first use "Copy" mode to filter out suspected corrupted files, then verify them one by one with readers such as CAJViewer before deciding whether to delete the original files.

A: This usually happens because the directory is occupied by another program, belongs to a protected system directory, or the current account does not have read permission. You can try: 1) close any CAJ reader or sync tool that may be using the files; 2) run this tool as administrator; 3) move the folder to a location accessible to ordinary users and then scan again.

A: It will not modify file contents or upload any files. The tool only reads a small number of bytes from the file header and tail for integrity checks. All scanning and copy/move operations are completed on the local disk, running fully offline without connecting to the internet or transmitting file data.