User list and download queue gone missing - any hope?

After running CCleaner and rebooting my system tonight, suddenly all data was gone when I tried to start Soulseek again. All my queued downloads and my entire userlist nowhere to be seen. I was simply greeted as a new user and required to login.

Upon visitting this page, I discovered the practical export function in the newest build, but perhaps too late?

I do have the old soulseek-client.dat file with almost 5 MB in my AppData/Local/SoulseekQt folder, but Soulseek does not seem to acknowledge it and always creates a new and almost empty one instead. I have checked several forum threads, but found no information that could help me any further.

So, I wonder, is there any way my old data can be accessed again? And if the .dat-file should be corrupted and of no use for Soulseek, is there any way to access the information included therein, at least the queue and the user list? A data export perhaps?

Any helpful suggestions would be greatly appreciated!