C510a Conversation function missing.

[#1]

Not sure what's going on but it's been happening ever since I got it, I would assume software problem on this one, often then sms Conversation function just dissapears and then come back a week or so later, it's really annoying since I use this function a lot. Do I need a software update or patch?

[#2]

No harm in performing a software update if it is available.

SE update service

http://dl-www.sonyericsson.com/cws/download/1/110/61/1309763183/Update_Service_Setup-2.11.7.13.exe

Alternatively you could perform a software repair using PC Companion if you are able to.

Connect your phone to the PC via the USB cable
The repair option on PC Companion (Support Zone --> Update --> Repair)

[Jake-SonyXperia]

I believe you are accidentally pressing the navigational key when inside the inbox which changes the sms back to default. Simply do the following,

Menu > Messaging > Inbox > Right navigational key. You should be back in Conversations.

[#4]

Yes, jake was right, found that out befotre I logged back in here haha. Sorry for late reply.

[Jake-SonyXperia]

No problem. I am glad you have it all working now