Save client data can occur for a number of reasons.
1. Anti virus interference caused by not setting exclusions correctly. (Bitdefender is a special case and requires more steps to it)
2. Having some kind of overlay or manager over it causing it to act up.
3. Not running the launcher as admin. Without admin it doesn't have the permissions it needs.
(The permission to run promt is not admin. It needs to be a right click and select run as administrator)
4. Its not stuck. (You can see if the launcher is stuck or not by if the slideshow at the bottom stops changing image every few seconds. If its still moving then its not stuck but something is preventing it)
5. Some process has started to act up. Doing a pc restart will fix that.
Your ping reducer isn't going to be related as save client data is a local stage