Knowledgebase Article – Outlook Instability Affecting cleanDocs

At various points over the last 12 months Microsoft has released Outlook KB patches that have introduced instability in the attachment list for Outlook emails. This has been across all Outlook versions, but most noticeable in Outlook 2010. In particular, workflows trying to remove attachments caused Outlook to remove the wrong attachment, not remove it at all, or report an error. This in turn made cleanDocs unable to correctly work with existing attachments to replace them with cleaned versions.

DocsCorp has released cleanDocs versions to meet the challenges of the Outlook issues as they have arisen. Until recent Microsoft KB patches were issued, cleanDocs 1.7.500.23 has been very successful at providing trouble-free operation despite the underlying Outlook issues.

Unfortunately, the most recent Microsoft patches have further changed the behavior of Outlook and required investigation and coding to best work around the new issues. This code is now available in and higher.

Detailed history of the issues

The first introduction of the issues was with the August/September 2015 Outlook KB updates:

Note that due to the nature of cumulative updates, these KBs may have been overridden and replaced by newer KB updates, and thus the specific numbers above may not be visible in Windows ‘installed updates’ list. However, the issue exists with each new cumulative Outlook KB update since.

The original symptoms were that occasionally emails had duplicate attachments after cleaning attachments. Upon closer inspection, it became apparent that the first attachment is not actually removed by Outlook, but rather put back in the list in a different place. The ‘duplication’ was the original attachment (never removed by Outlook) plus the new cleaned version. It is important to note that Outlook still reported the expected number of attachments, even though the original attachment stayed behind.

DocsCorp released cleanDocs 1.7 U5 (1.7.500.23), which counteracted the Outlook bug and allowed operations to work correctly for users. The workaround carried over into newer releases as well such as 1.7 U6.

Microsoft then released recent updates to Outlook as follows:

These releases contain a purported fix for “Attachments are rearranged, deleted, duplicated, or corrupted”. However, DocsCorp and customers have found that the fix was incomplete, and now causes different symptoms with the operation of Outlook and with cleanDocs.

Most issues with the duplicate attachments have been addressed (which then caused incompatibility with our workaround solutions in 1.7.500.23). DocsCorp has found that our workarounds implemented in 1.7 U5 or later (1.7.500.23) are now problematic after the newer KB’s are installed. We have urgently produced a cleanDocs 1.8 based version removing those workarounds and achieving the best possible results.

However, with the new KB patches, new permutations of the issues can now also cause corruption of embedded images (e.g. in email signatures). This happens when Outlook overrides one attachment with the content of another attachment. An even more common symptom is that Outlook completely locks the attachment list for editing (this issue can be demonstrated without any involvement from cleanDocs). cleanDocs is impacted in that it can read attachments, but when trying to remove existing attachments in order to replace with cleaned versions, Outlook throws an exception. Older versions of cleanDocs report this as ‘Failed to clean attachments’.

In the scenario where Outlook instability causes the attachment list to be locked, cleanDocs has been coded to catch that specific error and offer a special message detailing manual workarounds that can be applied to continue successfully sending that email. Unfortunately, automated approaches cannot be used in that scenario; the steps must be performed by the user.

DocsCorp has made urgent contact with Microsoft to try to get access directly to the development group responsible for these KB updates to Outlook.

Information for system administrators

When encountering any of its varied permutations of issues with attachments list in cleanDocs, DocsCorp recommends that Outlook be updated to the latest available Microsoft Outlook KB updates and then cleanDocs updated to cleanDocs Desktop or later. This version is now available on the customer portal.

Please contact DocsCorp Support for access to the latest builds and to ask any questions.