: The string of characters you've provided looks like a hash or a unique identifier used by download managers or software updates. If the file has no extension (like .pdf or .zip), your operating system won't know which program to use to open it.
No Extension? No Problem: How to Identify Almost Any File Type Archivo de Descarga yyyyyyy666660BBAF4E60ED8E24...
Could you tell me or what you were trying to download when it appeared? : The string of characters you've provided looks
If this was part of a specific download from a website, try to see if it completes with a proper name and extension. No Problem: How to Identify Almost Any File
: You can use a hex editor like HxD to look at the first few bytes (the "magic numbers") and match them against a File Signature List to see what it actually is.
