🛠️ Step 1: Unblock the Distribution Package

Because this package was downloaded from an internal network perimeter server, Windows blocks its contents by default:

1. Locate the downloaded file OTSRibbon.zip.
2. Right-click on the file and select Properties.
3. At the bottom of the General tab, look for the Security section.
4. Check the Unblock checkbox and click Apply / OK.

📁 Step 2: Deploy Content to Excel Safe Directory

To bypass strict Microsoft Office security policy restrictions, the files must be placed directly into Excel's native trusted Add-Ins repository:

1. Press Windows Key + R on your keyboard to open the Run dialog box.
2. Type or paste the following path and press Enter:
   %appdata%\Microsoft\AddIns
3. Extract and copy the files from the .zip package directly into this folder.
4. Ensure the folder contains the core unified assets and their required dependencies:
   • OTSRibbon.xll
   • OTSRibbon.xll.config
   • OTSRibbon.cer
   • +100 Additional application dependency DLLs

🔐 Step 3: Install Corporate Certificate (Requires Admin Rights)

To allow Excel to execute our internal signed code, the corporate certificate root must be trusted by the operating system:

1. Inside the %appdata%\Microsoft\AddIns folder, right-click on OTSRibbon.cer and select Install Certificate.
2. In the wizard, select Local Machine and click Next (This prompts the Windows UAC Admin elevation).
3. Select Place all certificates in the following store and click Browse....
4. Choose Trusted Root Certification Authorities and click OK.
5. Click Next, then click Finish. A confirmation box stating "The import was successful" will appear.

🛡️ Step 4: Configure Trusted Location Exception inside Microsoft Excel

Due to strict enterprise security policies (GPO) restricting user profile execution lanes, the target directory must be explicitly whitelisted within Excel's settings:

1. Open a blank workbook in Microsoft Excel (64-bit).
2. Navigate to File ➡️ Options ➡️ Trust Center.
3. Click the Trust Center Settings... button.
4. On the left menu, select Trusted Locations and click Add new location....
5. In the path field, paste the absolute directory path exactly:
   C:\Users\<YOUR_USERNAME>\AppData\Roaming\Microsoft\AddIns\
   (Make sure to replace <YOUR_USERNAME> with your actual Windows login name).
6. Check the box for "Subfolders of this location are also trusted" and click OK.
7. Close and completely exit Microsoft Excel to apply the configuration.

🔌 Step 5: Enable the Add-In inside Microsoft Excel

1. Reopen Microsoft Excel (64-bit).
2. Go to File ➡️ Options ➡️ Add-ins.
3. In the Manage dropdown list at the bottom, select Excel Add-ins and click Go...
4. Click Browse... (the wizard opens directly inside the correct trusted directory).
5. Select the file OTSRibbon.xll and click OK.
6. If a prompt appears regarding the digital publisher, you can now safely click Enable all code published by this publisher.