After completing a file download, IDM joins all downloaded parts into a single file and then writes the real file to the hard drive, and shows ‘download complete’ dialog. IDM does this normally to any file. With some security applications like Antivirus/Firewall/ Internet Security, you may get an error when IDM tries to write the file to the disk.

Here is that error: ‘An error occurred during download. Please try again’ Details:Cannot open local file for writing while joining downloaded parts into one file’.

READ:Fix ‘IDM cannot find 4 file(s) that are necessary for browser and system integration. Please reinstall IDM’

Panda Free Antivirus blocks IDM from writing the file to the disk

No matter how may times you try to resume the download again, it doesn’t finish, you’ll receive the same error.

We’ve found the Panda Free Antivirus installed on our computer as the culprit for this, we tried to download the file again after disabling Panda Free AV, it worked.

IDM cannot open local  file for writing while joining downloaded parts into one file

SEE: Fix IDM Setup’s Error ‘Could Not create process in unpacker Access is denied. ‘

If you’ve got this type of error with IDM (check the update added below), try to download the file by temporarily disabling antivirus or other security application you’re using on your system.

UPDATE: Latest Panda Free Antivirus 2016 v16.0.2 no longer blocks IDM file writings to the disk, so the issue has been fixed.