The "Error 997. Overlapped I/O operation is in progress" is found in the SEP_INST.log when installing or upgrading the Symantec Endpoint Protection (SEP) client. 

SEP_INST.log:

MSI (s) (48:94) [12:20:55:235]: SECREPAIR: Hash Database: C:\Windows\Installer\SourceHash{827E3EA6-85D1-4413-96D8-24B0F9B49967}
MSI (s) (48:94) [12:20:55:235]: SECREPAIR: SourceHash database file already exists. Deleting it.
MSI (s) (48:94) [12:20:55:297]: Note: 1: 2262 2: SourceHash 3: -2147287038
MSI (s) (48:94) [12:20:55:625]: SECREPAIR: New Hash Database creation complete.
MSI (s) (48:94) [12:20:55:875]: SECREPAIR: A general error running CryptAcquireContext
MSI (s) (48:94) [12:20:55:875]: SECREPAIR: Crypt Provider not initialized. Error:0
MSI (s) (48:94) [12:20:56:062]: SECREPAIR: A general error running CryptAcquireContext
MSI (s) (48:94) [12:20:56:062]: SECREPAIR: Crypt Provider not initialized. Error:0
MSI (s) (48:94) [12:20:56:233]: SECREPAIR: A general error running CryptAcquireContext
MSI (s) (48:94) [12:20:56:233]: SECREPAIR: Crypt Provider not initialized. Error:0
MSI (s) (48:94) [12:20:56:389]: SECREPAIR: A general error running CryptAcquireContext
MSI (s) (48:94) [12:20:56:389]: SECREPAIR: Crypt Provider not initialized. Error:0
MSI (s) (48:94) [12:20:56:561]: SECREPAIR: A general error running CryptAcquireContext
MSI (s) (48:94) [12:20:56:561]: SECREPAIR: Crypt Provider not initialized. Error:0
MSI (s) (48:94) [12:20:56:733]: SECREPAIR: A general error running CryptAcquireContext
MSI (s) (48:94) [12:20:56:733]: SECREPAIR: Crypt Provider not initialized. Error:997
MSI (s) (48:94) [12:20:56:733]: SECUREREPAIR: Failed to CreateContentHash of the file: Program Files\Symantec\Name\Version\Bin64\SessionStub.exe: for computing its hash. Error: 997
MSI (s) (48:94) [12:20:56:733]: SECREPAIR: Failed to create hash for the install source files
MSI (s) (48:94) [12:20:56:733]: SECUREREPAIR: SecureRepair Failed. Error code: 3e5F9F834B8
Action start 12:20:55: ResolveSource.
MSI (s) (48:94) [12:23:09:988]:
MSI (c) (5C:44) [12:20:56:811]: Font created. Charset: Req=0, Ret=0, Font: Req=MS Shell Dlg, Ret=MS Shell Dlg

Error 997. Overlapped I/O operation is in progress.

Either incorrect permissions on the C:\ProgramData\Microsoft\Crypto\RSA\S-1-5-18 folder.

OR

Per Microsoft's blog, patch KB2918614 appears to have caused this installation issue:

https://answers.microsoft.com/en-us/windows/forum/windows8_1-windows_install/kb2918614-breaks-windows-installer-service/3d75a1c2-114a-4241-a527-35b536edc158

First, verify the permissions for the C:\ProgramData\Microsoft\Crypto\RSA\S-1-5-18 folder.
Both SYSTEM and Administrators need to have Full Control.
 

If the above does not resolve it then look at the Microsoft updates that have been known to impact Microsft Cryptography services.

See "Known issue 2" at the following link for workaround steps related to the SecureRepairPolicy: https://support.microsoft.com/en-us/help/2918614

Applies To
Windows 7 Professional (Windows 8 and possibly others are affected)