How to reduce size of mail app in Windows 10 Mobile?

[Windows Central Question]

The mail app on my Lumia 640 is 1.24GB which is stopping me installing updates. I can only get them installed by uninstalling several apps.
1.24GB is ridiculous, as it isn't the actual mail but that of the app. The data is trivial in comparison .
Surely this is wrong? How can I get the app down to a sensible size?

 

[LumPhile]

The app is less than 200mb on my 640. You could try uninstalling then reinstalling.

 

[T Moore]

How do you know it isn't the actual mail but that of the app?
Have you gone to the sync settings of the accounts? There are options for mail sync to download content that range from the last 3 days to 'any time'

 

[Salamat1]

Reading about this issue elsewhere, the only solution I've seen so far is to backup the phone, hard reset it, decline to restore the backup, upgrade the OS, then restore the backup! (Other people have deleted their mail accounts and reduced the syncing time and this has had no effect on the size.)

Under version 10.0.15063.251 / 1703 it looks like there should be an 'app reset' option for 'Mail and Calendar' but this doesn't seem to be working. Is it working for anyone else? Has anyone tried it, and has it had any effect on the size?

 

[LumPhile]

Mine has been steadily creeping up in recent times: It has moved from around 200mb to close to 300mb at the moment. I had naïvely suggested uninstalling/reinstalling, not realizing that it can't be uninstalled.
Sad to hear that the reset function in CU seems to have no effect; this feature is the primary reason why I wanted CU. Having read through some of the early reviews of CU, I'm beginning to consider myself fortunate that the update has not yet been offered to me!

 

[Salamat1]

I have to confess I didn't realise it was the 'CU' until after it started! There were no 'Bells & Whistles' to say that what it was, I just thought it was a routine update when I did a 'Check for Updates'!

(Another side effect of the installation was that none of the apps on my SD card would start! I had to uninstall, then reinstall every one! It's also broken a Barclays Bank app, as it thinks the phone's jailbroken!)

When you do get it offered, it might be an idea to hold off for a month or two!

 

[LumPhile]

Has anyone discovered a solution for this very annoying problem? Mine has been steadily creeping up, and I don't want to exercise the nuclear option of a reset: Seems kinda extreme just to flush extraneous data from one app