[22:51:10] [Server thread/INFO]: This server is running CraftBukkit version git-Bukkit-1.7.2-R0.3-56-g3779cff-b3072jnks (MC: 1.7.9) (Implementing API version 1.7.9-R0.1-SNAPSHOT)

iConomy v7.0
Fe v0.8-SNAPSHOT-b49

This may not be a Vault issue. Running "/vault-convert iConomy7 Fe" insists that it "Could not find iConomy7 loaded on the server, check your spelling" until Fe is unloaded or removed. Vice versa is also true.

iirc Niji never made iCo7, he erroneously renamed it that as an april fools joke but the actual plugin still registers as Iconomy6. Please verify what Vault is actually saying it's loaded as.

That's what I thought so I tried "iConomy6", but it turns out he did update the version number. Vault seems to recognize it as 7 (at least when running without Fe installed).

[16:31:52 INFO]: [Vault] Vault v1.4.1-b436 Information
[16:31:52 INFO]: [Vault] Economy: iConomy 7 [iConomy 7, Essentials Economy]
[16:31:52 INFO]: [Vault] Permission: PermissionsEx [PermissionsEx, SuperPerms]
[16:31:52 INFO]: [Vault] Chat: PermissionsEx_Chat [PermissionsEx_Chat, iChat]

can you show the full Vault messages when you install Fe?

it looks like it registering as Essentials Eco, not iConomy.

Hmm... well we do have Essentials installed (not for economy), but I see what you mean - iConomy 7 is detected as both "iConomy 7" and "Essentials Economy"! And when we throw Fe into the mix, it overpowers the "iConomy 7" half. That's very strange!

What can be done for this?

This is with Fe installed along with iConomy.

[19:40:27 INFO]: [Vault] Vault v1.4.1-b436 Information
[19:40:27 INFO]: [Vault] Economy: Fe [Fe, Essentials Economy]
[19:40:27 INFO]: [Vault] Permission: PermissionsEx [PermissionsEx, SuperPerms]
[19:40:27 INFO]: [Vault] Chat: PermissionsEx_Chat [PermissionsEx_Chat, iChat]

This is just Fe.

[19:47:14 INFO]: [Vault] Vault v1.4.1-b436 Information
[19:47:14 INFO]: [Vault] Economy: Fe [Fe]
[19:47:14 INFO]: [Vault] Permission: PermissionsEx [PermissionsEx, SuperPerms]
[19:47:14 INFO]: [Vault] Chat: PermissionsEx_Chat [PermissionsEx_Chat, iChat]

what happens if you don't have essentials installed?

With no Essentials, but Fe AND iConomy installed:

[19:47:14 INFO]: [Vault] Vault v1.4.1-b436 Information
[19:47:14 INFO]: [Vault] Economy: Fe [Fe]
[19:47:14 INFO]: [Vault] Permission: PermissionsEx [PermissionsEx, SuperPerms]
[19:47:14 INFO]: [Vault] Chat: PermissionsEx_Chat [PermissionsEx_Chat, iChat]

With no Essentials, but just iConomy installed:

[22:57:49 INFO]: [Vault] Vault v1.4.1-b436 Information
[22:57:49 INFO]: [Vault] Economy: iConomy 7 [iConomy 7]
[22:57:49 INFO]: [Vault] Permission: PermissionsEx [PermissionsEx, SuperPerms]
[22:57:49 INFO]: [Vault] Chat: PermissionsEx_Chat [PermissionsEx_Chat, iChat]

what version of iCo and where was it downloaded from?
Unfortunately, I have no idea why it's only registering one when you have both installed, and the convert method is a as-is method I'm not going to go through and patch it if it's not working. So if this doesn't work you're going to have to convert some other way.

It's off BukkitDev, here's from the plugin.yml:

General Data

name: iConomy
main: com.iCo6.iConomy
version: 7.0

I wish you had told me that from the beginning :( The authors of Fe recently removed their native conversion code and told everyone to use Vault, so that's very disappointing.

Yes, it is. Fe unregisters every other Vault economy service. I've changed this in this commit: niccholaspage/Fe@74787d7

Fe will no longer unregister other Vault economy services, so conversion should work.

Could this be related?
https://github.com/niccholaspage/Fe/blob/master/src/org/melonbrew/fe/Fe.java#L364

That did the trick! Thanks @niccholaspage

[18:28:51 INFO]: [Vault] Vault v1.4.1-b436 Information
[18:28:51 INFO]: [Vault] Economy: Fe [Fe, iConomy 7]
[18:28:51 INFO]: [Vault] Permission: PermissionsEx [PermissionsEx, SuperPerms]
[18:28:51 INFO]: [Vault] Chat: PermissionsEx_Chat [PermissionsEx_Chat, iChat]