Attachments may be missing after you convert OLM files to PST for a few common reasons, and most of them are easy to fix.

One major reason is that the “exclude attachments” option might have been enabled during conversion. Some tools provide this feature to reduce file size, so if it’s checked, attachments won’t be included in the final PST. Another possibility is an incomplete or interrupted conversion process, which can skip large or embedded attachments.

Corruption in the original OLM file can also cause missing attachments, especially if the file was damaged or not exported properly from Mac Outlook. In some cases, using an unreliable or basic converter may fail to handle attachments correctly, particularly large files or complex formats.

To avoid this, make sure you use a reliable tool like SysInfo OLM Converter, keep the attachment settings enabled, and verify the preview before starting the conversion. Also, ensure the process completes without interruption. This helps ensure all emails and their attachments are fully preserved in the PST file.
Read more: https://www.sysinfotools.com/olm-converter.php