You may try system restore and check if it helps if the issue happened after any changes.
System Restore can return your PC's system files and programs to a time when everything was working fine, potentially preventing hours of troubleshooting headaches. It will not affect your documents, pictures, or other data.
Please refer to the link: http://windows.microsoft.com/en-US/windows-vista/What-is-System-Restore
Or you can also use the old-school method of downloading ffmpeg.dll from the dll database website. This is one of the many websites that you can use to download the missing DLL files. Any given file would have a number of versions and you can choose any depending upon the version of OS you use. Always opt for the latest version.
I have the same problem and my 2500 SC is now lost in my Poloniex wallet. Its so chaotic.
I opened an account on Hitbtc and exchanged about 3000 sc so far with absolutely no issues.
Anyone has any idea why sc is falling down?
@SandBlock Sia-UI-v1.3.1 synchronized block height:139885 ；No. 2.1 has not received SC by now。I don't know what to do！ It is not useful to fill in the Backup Wallet password in Recover Seed。
Make sure you are using the latest version of Sia-UI (v1.3.1) since the old version of Sia-UI is incompatible with the current network.
Compare your blockheight with https://siastats.info, the blockheight in your wallet should be the same or higher than the blockheight shown on the website.
