I’ve been using the Mail app since September 2015 but also rely on Windows Live Mail 2012 because I do not trust the Mail app. In the beginning it would not synch at all, so the app was useless. With a later update of W 10 in November the sync issue disappeared, and so I was trusting it. However since quite a while my trust in the app fades away again. Reason as one example: The Sent Items folder shows only the last 6 sent emails, all earlier ones are not showing up despite the setting to show all. This appears with the account of outlook.com. In the second account which is NOT outlook.com, I have two folders for sent emails, of which one is called Sent Mail and the other Sent Items. the reason is as follows: originally on the providers website all sent emails were in the Sent Items folder but the would not show up in the same folder of the Mail app. So on the website I moved all the sent email from the Sent Items folder to the Sent Mail folder. Then I created a Sent Mail folder in the Mail app, and guess what happened after syncing they were suddenly all shown in the Mail app. However, since a couple of days now it shows only the last six sent emails. Pretty weird isn’t it! Now when I send an email the email appears in the Sent Items folder. I move emails then from the Sent Items folder to the Sent Mail folder in the Mail app.
For that reason I have reactivated Windows Live Mail 2012, and use it rather than the Mail app!
I do not want to say that this is the fault of the Mail app because for that I have no proof. Maybe the Mail app and its files are corrupted or not. I have been looking for a complete solution, and there seems to be only one: Uninstall the Mail app and reinstall it. I do know the procedure which is clearly shown on several websites and I can perform the procedure w/o a problem. The question is whether this would resolve the issue?? A reinstallation would do a complete new set-up and I then have to recreate the two accounts with all settings. I know that the procedure would also kill and reinstall the calendar and I have to redo all the entries. The last question is, whether the uninstallation would also remove any email data from their appropriate folders so that nothing is left over which in the end at reinstallation the same issue reoccurs.
I know this pretty stark of a post and I would appreciate any good advice, maybe from those who went through a similar issue.