I cant save lync conversations now; It was working fine for me a week back. When I checked out lync options/ Personal....  cant check the box to save IM conversations in email.

Is the "Save IM Conversations in my email Conversation History folder" setting in your Lync Option disabled and grayed-out? 
If Yes, then your Lync administrator might have disabled that feature in your environment through Group Policy.
For older version of Lync there was a registry key for EnableIMAutoArchiving which could be set for controlling this feature but in Lync 2013, this registry key has no effect.

Thanks

agree w/ Arijit_Dey, check with your Lync admin and see why they changed the policy.  usually it's security department complaining about documentation retention and legal concerns

Is the "Save IM Conversations in my email Conversation History folder" setting in your Lync Option disabled and grayed-out? 
If Yes, then your Lync administrator might have disabled that feature in your environment through Group Policy.
For older version of Lync there was a registry key for EnableIMAutoArchiving which could be set for controlling this feature but in Lync 2013, this registry key has no effect.

Thanks

• Proposed as answer by Eason HuangMicrosoft contingent staff, Moderator 22 hours 54 minutes ago

Is the "Save IM Conversations in my email Conversation History folder" setting in your Lync Option disabled and grayed-out? 
If Yes, then your Lync administrator might have disabled that feature in your environment through Group Policy.
For older version of Lync there was a registry key for EnableIMAutoArchiving which could be set for controlling this feature but in Lync 2013, this registry key has no effect.

Thanks

• Proposed as answer by Eason HuangMicrosoft contingent staff, Moderator Sunday, May 31, 2015 8:30 AM

Is the "Save IM Conversations in my email Conversation History folder" setting in your Lync Option disabled and grayed-out? 
If Yes, then your Lync administrator might have disabled that feature in your environment through Group Policy.
For older version of Lync there was a registry key for EnableIMAutoArchiving which could be set for controlling this feature but in Lync 2013, this registry key has no effect.

Thanks

• Proposed as answer by Eason HuangMicrosoft contingent staff, Moderator Sunday, May 31, 2015 8:30 AM
• Marked as answer by Eason HuangMicrosoft contingent staff, Moderator 23 hours 34 minutes ago

Hi,

One item to remember is that EnableIMAutoArchiving just stops the automatic saving of IMs to conversation history.  A user could still use the CTRL+S to save it themselves.  You would need to also enable the DisableSavingIM client policy tag to completely stop saving of all IMs.

Best Regards,
Eason Huang