Unreal Editor and other source files disappeared

My unreal-editor just disappeared from the source engine folder, this is not the first time for me and I am sure that I DIDN’T DELETE OR MOVED THE FILES ANYWHERE. Since I had this before, I decided to copy the unreal-editor.exe source version in advance and this happened, I launched it and errors appeared about the absence of unreal-editor-core.dll, unreal-editor-coreuobject.dll, unreal-editor-inputcore.dll, unreal-editor-engine.dll. My nerves are already giving out from the fact that all the deadlines and plans are collapsing.Help me

Could it be a virus or a hard drive problem?

I don’t think soo, my files disappeared after I rebuilt the project.