The following was posted by a member on ILTA's forums:
"Scenario: You use an iPhone or iPAD with latest version 9.3 iOS. You receive a message with certain multiple attachments and immediately forward it to others to review.
Problem: The multiple attachments you sent may be combined into a single attachment when the recipient gets it.
If received by recipient in Outlook: In most circumstances the received attachment attempts to open and reports a failure.
If received by recipient on Mobile Device: Sometimes you can open it and see the first attachment and not others. Other times the attachment opens with a blacked out window. Other times the attachment doesn’t even show up.
WORK AROUND: We have determined that if you first open the pdfs of the iPhone before forwarding, they always arrive intact.
TIP: If you receive an email on iPhone with multiple attachments and you don’t want to open each one, you can first forward to yourself and see if they come across as they should. If they come intact to you, you can forward to others. If it is corrupt on your device you will either have to either forward using Outlook or take the time to open each original before using the iPhone to forward to effect a successful transmission. We see some limited posts on the Internet but nothing concrete as to the root cause.
If your curious about the details thus far – here is where we are with testing:
It is a result of the iPhone Forward function verses the receive function. It can happen on internal communications so nothing to do with transmission over the net or how someone else's system is configured or how they go about attaching the docs.
We conducted over 100 tests to try and nail down the offending attachment formats. PDF version 1.4 and 1.7 seem to fail all the time. PDF 1.5 which is created by our Nuance app has been solid and works unless a 1.4 or 1.7 version attachment is on the email as well. We have found a few suspect 1.5 files recently however...
We got it to fail with image files only. If only Word docs were attached, thus far it seems fine. If we mixed word docs in with problem pdf or problem image files we could again reproduce the trouble and the word doc was no longer usable.
We know we hit trouble whenever the recipient of the iPhone attachment displays this on their iPhone:
This message was downloaded as plain text.
Download full message
We can 100% replicate the problem with our own email communications within the firm – eliminates the need to test with outside firms. We can duplicate with pdf files attorneys created in-house via Westlaw research (generates Apache origination with PDF version 1.4). I can also reproduce it with a technical document I received from Mimecast.
I cannot duplicate with Nuance PDF converted documents which is what we use and generates the version 1.5 documents. We created and attached dozens without error multiple times.
It is ONLY reproducible on the iOS platform. The Blackberry and Android devices do NOT exhibit this behavior.
We have also replicated it on a iPAD device with the newest 9.3 iOS version.
We have replicated with mail boxes on our existing 2010 exchange server and our new 2016 server which we are migrating to.
We have also replicated with picture files that I had downloaded to my c drive from my iphone.
We can reproduce it on multiple carriers (AT&T and Verizon for example)
We can replicate it on both wi-fi and cellular networks."
