This is Windows telling you that AxCrypt (acting as ‘you’) does not have permissions to the folder or the file in question. This can be caused by many things, but they are not AxCrypt-related. If you have moved the disk from another Windows-computer or if you have re-installed Windows you may need to “take ownership”. If you have encrypted the files/folder also with Windows EFS (Encrypting File System) *and* moved the files or re-installed Windows, you need to decrypt them in the original Windows or using backed up recovery certificates. Use Google to find out more about the mentioned situations. It is likely you cannot copy and/or delete the file without AxCrypt directly from Windows Explorer either – thus not an AxCrypt-related issue.
Are you really sure it’s not EFS? Can you send a screen shot of such a file in Windows Explorer? Or check properties and ensure that the “Encrypt Contents to Secure Data” is *not* checked? Note that the way EFS-files are distinguished has changed in Windows 10 – now it’s a little small padlock icon overlay, before the text of the file name was in green text.
The situation with Dual Boot you describe is a typical scenario where this will happen if it’s EFS-encrypted in Windows 10 and you then try to access them in Windows 7.