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thunderbird adds 5 MB to my emails with attachments

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Hi, I am on a 8.1 win desktop and use Thunderbird for my email (v38.2.0). Ever since Mozilla did a major update on Thunderbird, everything changed sooo much I am really not liking this program like I did before. I am getting slow start up, program not responding or hanging with every send of an email. I just attached a 15.9 mb pdf file to an email and it tells me that I am about to send a 21.4 mb file! Where is the extra 5mbs of size coming from. I have removed all add-ons that I installed in the last year and nothing changes! I have gone on Mozilla Support, went through 3 different procedures recommended, and even did a registry change that sounded logical and still nothing. The only thing I can think of for the hanging is the fact I have multiple folders but I monitor size and never had a problem in the last 5 years I have been using Thunderbird with all the same files...no, I lied, MORE folders and files than I have now!! HELP! What is wrong with this build, and where is the extra size on my text emails is coming from??

All Replies (5)

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I am getting slow start up, program not responding or hanging with every send of an email.

What is your anti-virus software?

I just attached a 15.9 mb pdf file to an email and it tells me that I am about to send a 21.4 mb file!

This is expected, and it isn't specific to Thunderbird. Binary attachments need to be converted to text, hence the additional overhead. See http://ask-leo.com/why_are_emailed_attachments_larger_than_the_original_file.html

Modified by christ1

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Hi Christ1,

Thanks for sending me the info on the larger files when sending. I have always seen some increase, that was given, and the article talks about a 37% increase but I have never had such an increase until now and I have been sending these same large files for years. I would maybe get a 10% increase but never 30%+! I have to think it is not the file but the program that at the same time as causing these phantom increase is having hangs and freezes.

So what has changed to make this build so labored and can I go back to the previous build?

Oh... sorry. My anti-virus is the same as I have had for the last 3+ years. MalwareBytes, and Windows Defender.

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Chosen Solution

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niteowl doesn't like to reply - so I'm marking this solved

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Just to follow up on this issue, I have gone into safe mode and the additional file sizing remains. I do not ever remember a 20 mb file attachment growing to 27mb when sent in the past as I experienced just today and still believe that the new upgrade to TB38 has been the first instances that I have experienced a 25% increase to my attachment size.

I gave up defending this position with the examples that you have offered but I still remain poised. @o@

You can close this now. PS I am new to moz support forum (never needed till TB38 upgrade!! :-D