Fix 0X000009C9: No loader specified in boot-block file

Quick answer: Check the boot-block definition file (usually RPLSVC.INI or the database) and make sure the loader line points to a valid boot loader file. If it's missing, add it. Then restart the Remote Boot service.

What's going on with error 0X000009C9?

This is a classic Remote Boot (RPL — Remote Program Load) error from Windows NT 4.0 and early Windows 2000 Server. You see it when a client machine tries to boot from the network and the server that's supposed to dish out the boot files can't find a loader entry in its configuration. The full error message is: No loader is specified in the NERR_NoRplBootSystem boot-block definition file

The trigger is almost always a manual edit to the RPL database, or a corrupted RPLSVC.INI file after a server crash or botched backup restore. I've seen it happen when someone copied over the RPL folder from a different server build without updating the paths.

The server is looking at a specific boot-block definition — say for a DOS, Windows 3.1, or Windows 95 network boot — and the entry for that block is missing the loader= line. Without that, the server doesn't know which file to send to the client. It's like having a key ring with no keys.

How to fix it — step by step

These steps assume you're on a Windows NT 4.0 or Windows 2000 Server machine running the Remote Boot service (RPLSVC). You'll need Administrator rights.

Open the RPL database file.
On Windows NT 4.0, it's C:\Winnt\System32\Drivers\Etc\RPLSVC.INI. On Windows 2000 Server, it's C:\WINNT\System32\RPL\RPLSVC.INI. Open it in Notepad or any text editor. Expected outcome: You'll see sections like [RemoteBootDatabase] and [BootBlocks]. If the file is empty or missing, you'll need to restore from backup.
Find the problem boot-block definition.
Look under the [BootBlocks] section. Each boot-block has a heading like [BBLOCK_NAME] (e.g., [DOS622] or [WIN95]) followed by key-value pairs. Locate the one that matches the client machine's adapter or profile. If you don't know which one, look at the client's MAC address in the [Clients] section — it will point to a profile, which points to a boot-block. Expected outcome: You should see lines like loader=bbldr.exe, message=msmtrp.msg, vendor=Microsoft. If loader= is missing, that's your culprit.
Add the missing loader line.
For a standard DOS or Windows 95 boot block, the loader is typically bbldr.exe (the boot block loader) or rplboot.com for older LAN Manager setups. Add this line under the boot-block heading:
```
loader=bbldr.exe
```
Make sure the file bbldr.exe actually exists in the C:\WINNT\System32\RPL\ folder (or wherever your RPL files live). If not, you'll need to copy it from the original server CD or a working server. Expected outcome: The line appears right after the heading, before any other keys.
Save the file and close Notepad.
Don't change anything else unless you're sure it's wrong. A single typo will break the whole service.
Restart the Remote Boot service.
Open a command prompt as Administrator. Run:
```
net stop rplsvc && net start rplsvc
```
Or you can go to Services.msc, find "Remote Boot Service", right-click and choose Restart. Expected outcome: The service starts without error. If it fails to start, check the Application Event Log for the exact reason — usually a syntax error in the INI file.
Test the client boot.
Boot the client machine from the network again. Expected outcome: It should now download the loader file and proceed to the next stage (like loading DOS or Windows). If you still get the same error, you may have multiple boot-blocks missing the loader.

Alternative fixes if the main one doesn't work

Check for corrupted or missing boot loader files

Sometimes the INI file is fine, but the actual loader file (like bbldr.exe or rplboot.com) is missing or corrupted. Go to C:\WINNT\System32\RPL\ and look for bbldr.exe. If it's not there, copy it from the original installation media or from a working server of the same OS version. The file is about 3.5 KB on NT 4.0 and slightly larger on Windows 2000.

Rebuild the RPL database from scratch

If the INI file is a mess and you have no clean backup, you can delete it and recreate it using the RPLMGR.EXE tool (Remote Boot Manager). Go to Start → Programs → Administrative Tools → Remote Boot Manager. This tool lets you define boot-blocks, profiles, and clients manually. It's tedious, but it ensures the entries are syntactically correct. The tool won't let you save a boot-block without a loader.

Check for duplicate boot-block names

I've seen cases where two boot-blocks have the same name in the INI file. The service gets confused and picks the wrong one, which might be missing the loader. Search the INI file for repeated [BBLOCK_???] headings. If you find duplicates, rename one or remove it.

Preventing this in the future

Don't edit RPLSVC.INI by hand unless you absolutely have to. Use the Remote Boot Manager tool for any changes — it validates entries before saving. If you must edit the INI file, make a backup copy first (rename it to RPLSVC.INI.BAK). Also, when you restore the RPL folder from a backup, restore the entire folder tree (C:\WINNT\System32\RPL\ and C:\WINNT\System32\Drivers\Etc\), not just the INI file — the loader files must match the version of the OS that generated them. Mixing NT 4.0 files with Windows 2000 files will give you this exact error.