Just want to share few comments might help the OP
If you are running in your ssis package in the Designer mode i.e. in SSDT then you need to make sure you have 32 bit ACE driver. Doesn't matter if you are using a 64 bit OS.
If you want to run your ssis package using DTEXE Utility and your OS is 64 bit, then you have two option whether to run in 32 bit or you want to run it in 64 bit.
For more detail you can refer to Installing the Microsoft.ACE.OLEDB.12.0 Provider for Both 64-bit and 32-bit Processing
Hope it helps.
There is a small nuance to be added to this. When you execute a package from SSDT, it spawns a DTExec.exe process to perform the execution.
If you are using a 64-bit OS, by default the 64-bit version of DTExec.exe will be spawned – and it is only by checking the 'use 32-bit runtime' flag that you force SSDT to spawn the 32-bit version of DTExec.
Good catch Phil. Excel never have been a good friend of SSIS after all 😛