Folder suddenly turned into exe file

It's a tough one. In a situation like this the solution is to go back to your backup but sadly you don't have a full backup.

You might find your only option is to purchase something like StellarPhoenixMacDataRecovery which can scan your drive for lost files. It's about £60 here in the UK. I think you can use a trial version to see if the files can, at least, be found before laying out any cash.

It could be that the drive has failed. Flash memory is not suitable for archival storage.

They usually fail to a read-only state.

There have been various instances of folders losing their directory bit and show up as a unknown file type. Since a folder must have an executable flag set, it shows up in Finder as an executable file.

I don't know how to correct that, though.

Have you tried putting the drive in another computer?

If you can, try to restore your backed-up photos to another machine. At least that way you know those are safe.

When did the files disappear? Was it recently? If so, you might be able to use Time Machine to recover them (despite having no external Time Machine drive plugged in) as it tries to perform internal backups if space allows.

It's also worth running Disk Utility and performing First Aid on the internal drive. The directory may have benn corrupted and a repair might bring back apparent lost files.

All of that is completely normal, except the folders you created at the root level of the startup drive instead of in a user home.

You altered the Finder preferences to show hidden files.

With respect, I disagree about viruses.

Flashback malware infected over 600,000 Mac computers in April 2012; designed to steal user's personal information, including account login credentials.

OSX/KitM.A virus - Infected a small number of Mac computers in May 2013; designed to take screenshots of a user's desktop and upload to one of several websites.

OSX.PROTON - Infected thousands of Mac computers in 2017; designed to steal user's account credentials by accessing the macOS Keychain app.

OSX/MaMi - Infected several thousand or more Mac computers in January 2018; designed to allow a person to view a computer's Internet traffic, also called "snooping."

Some malware is blocked by macOS but now all. MalwareBytes often picks up malware that gets through.

That said, I don't think the .exe issue is malware related.

You think its better to put those additional folders somewhere else? Could that be confusing the finder?

No, it doesn't confuse the Finder, but it is not the place to store user data. If you need a shared folder, put it in /Users/Shared/. If it isn't shared, put it in your home under Documents or somewhere else.

If it needs to be private, then you need to either create the folder in one of the protected subfolders of your Home (Documents, Desktop, Pictures, Music, Downloads), or change the permissions on the newly created folder to remove the group (Staff) and set everyone to "no access."

A virus or malware didn't cause the problem with the folder. It does happen rarely as I have seen reports of it here on ASC. I have not seen a solution, though.

You should always have a backup, and if you are using flash media as a permanent storage medium, you are choosing poorly. They are not reliable enough for that purpose.

Very odd indeed. Possibly a silly question but do you have a Time Machine backup of the drive?

The highlighted one? Looks normal to me.