Why can’t I send ISO files by email?
A small program may fit as an email attachment. A disk image will not. An installation image is several GB. A full computer backup is tens or hundreds of GB. Gmail does not accept attachments over 25 MB, and Outlook does not accept attachments over approximately 20 MB.
Splitting the image does not solve the problem. If one part is missing, the file will not open. We do not combine those parts. If the file is very large and you have enough time, shipping an external drive is also an option. With a link, the recipient downloads the file without the drive being shipped.
The file the recipient mounts should be the same image you uploaded.
| Method | What happens | For installations and backups |
|---|---|---|
| Gmail or Outlook attachment | Attachments over 20–25 MB will not send | Not suitable |
| Splitting the image | It will not open if a part is missing | Not suitable |
| Zipping it again | The size barely decreases | Not enough |
| Shared drive | Has a storage quota and requires an account | Use with care |
| SendGB link | The image is not opened or sent as an attachment | Suitable for delivery |
The example above is an installation that fits within the free limit: an ISO, a Mac driver, a network card package, and two short notes. A full disk backup is much larger than this example.
Opening an image vs. sending it as is
Opening an image means mounting the image file as a disk. The recipient’s computer does this. We do not. We do not convert ISO to DMG or VHD to VMDK. We do not write files to a USB drive, either.
A checksum is used to check whether the entire file has been downloaded. You calculate it. You include it in a note. We do not generate checksums or test the image.
| Split or converted copy | Image sent as is | |
|---|---|---|
| Purpose | Fit into an email | Install or restore from a backup |
| Format | Split or changed | The format you saved |
| Missing part | The file will not open | A single file downloads |
| Testing | Your responsibility | We do not open it |
| What we do | We do not combine or convert files | We leave the file untouched |
The same applies to virtual disks. VHD and VMDK files are virtual machine disks. We do not reduce their size. We do not start the virtual machine.
What should you include with the image?
An installation image may be a single file. Without drivers and a note, the recipient may get stuck.
| File | Purpose | If missing |
|---|---|---|
| ISO or DMG | The installation itself | The disk stays empty |
| Driver | Network, display, or disk controller | The installation may not detect the network |
| Checksum | Check that the entire file has been downloaded | File corruption is noticed later |
| Short note | Identify each image | The recipient mounts the wrong file |
| Virtual disk | The virtual machine’s disk | Must be included separately |
You put these in the same folder. We do not extract drivers from the image. The folder structure stays intact when the recipient downloads the entire transfer. See the guide to sending folders for details.
Keep the installation file from being publicly accessible. Add a password. Send the password separately from the link.
Is 5 GB enough for a disk image?
It is enough for a small installation image. It is not enough for a full backup. The limit is the total transfer size, not the number of files. Free transfers stop at 5 GB. We do not guarantee how many files you can include in a transfer.
| What you are sending | Typical size | Which option is enough |
|---|---|---|
| Small utility image | Under 5 GB | Free; up to 90 days for files up to 250 MB, 7 days above that |
| Large installation image | Often close to or over 5 GB | Free if it fits; SendGB Extra if it exceeds the limit |
| Virtual machine disk | Can be tens of GB | SendGB Extra, 500 GB per transfer |
| Full computer backup | Can be hundreds of GB | SendGB Extra or SendGB Exceed |
| Image over 1 TB | A single file | Will not fit in a single transfer |
SendGB Extra starts at €29.90 per year. It includes 1 TB of storage. SendGB Extra keeps files for up to 1 year. It is suitable for frequently sending large backups. The limit per transfer is 500 GB.
SendGB Exceed requires no membership. A 1 TB transfer costs €9.99. The code can be used once and is valid for 1 year. The link stays available for 7 days. It is sufficient for occasionally sending a single image over 500 GB. We cannot send more than 1 TB as a single file.
If you enter your email address, you receive one notification when a download starts. With email delivery, you are notified once per recipient. With link delivery, you are notified once per transfer. If the same person downloads again, you will not receive another email. The notification does not confirm that the entire image has been downloaded or opened.
How to send
- 1
Add the image
Add the ISO, DMG, or virtual disk file to the upload box. You can include drivers and a short note in the same transfer. The free limit is 5 GB total. If a single file exceeds that limit, you need SendGB Extra or SendGB Exceed.
- 2
Send the link
Email the link to the recipient or copy and paste it into a message. Add a password for the installation file. Send the password separately from the link. If you enter your email address, you receive one notification when a download starts.
- 3
The recipient downloads
The recipient downloads from the link and does not create an account. The image is not opened on the download page. They download the file and mount it on their own computer. Free transfers over 250 MB stay available for 7 days. Free transfers up to 250 MB stay available for up to 90 days. SendGB Extra keeps files for up to 1 year.
What happens to your file?
- We leave the file untouched. The image is not opened, split, or converted.
- ISO, DMG, IMG, VHD, and VMDK files download as they are.
- The accompanying drivers and note go in the same transfer.
- If you enter your email address, you receive one notification when someone starts downloading.
What we don’t do
- We do not test the image. We do not check whether it opens or can be written to a disk.
- We do not generate a checksum. You calculate it and include it in a note.
- We do not combine split files. More than 1 TB will not fit in a single transfer.
- A download notification does not confirm that the entire file has been downloaded.
Frequently asked questions
What is a disk image?
It is a copy of a disk or installation stored as a single file. An ISO is often an installation image or a disk image that can be written to a USB drive. A DMG is a Mac disk image. An IMG is a raw copy. VHD and VMDK files are virtual machine disks. We send all of them without opening them.
Can a disk image get corrupted during transfer?
We do not open, compress, or convert the file. We do not turn an ISO into a DMG. An incompletely downloaded image may not open. We do not verify that the download is complete. Calculate a checksum and include it in a note.
What if 5 GB is not enough?
If a single file exceeds 5 GB, it cannot be sent in a free transfer. Installation images are often close to or above this limit. A full disk backup is much larger. Do not split it across several free transfers. We do not combine the parts.
Will compressing it again help?
Usually not. The contents of an installation image are already compressed. A raw disk copy will not shrink much when zipped, either. Send the file as it is.
Can the recipient open the image on the download page?
No. ISO, DMG, and virtual disk files are not opened on the download page. The recipient downloads the file and mounts it on their own system or writes it to a USB drive. We do not do this. No account is required.
Can I send drivers and a note together?
Yes, if you include them in the same transfer. If the network or display drivers are not in the image, add them to the folder yourself. We do not look for those files. The folder structure stays intact when the recipient downloads the entire transfer.
Why does Gmail reject disk images?
Gmail does not accept attachments over 25 MB, and Outlook does not accept attachments over approximately 20 MB. A disk image is hundreds of times larger than those limits. A link is not an attachment. The file is not embedded in the message. No add-on is required.
Can I transfer virtual disk images too?
Yes, VHD and VMDK files download as they are. We do not shrink the virtual disk or start the virtual machine. The file transfers at the same size it occupies on your computer.
Will I be notified when the recipient starts downloading?
Yes, if you enter your email address. With email delivery, you are notified once per recipient. With link delivery, you are notified once per transfer. The notification tells you that the download has started. It does not confirm that the entire file has been downloaded. It does not mean the image has been opened.
Which transfer limit should I choose?
An installation image under 5 GB can be sent free. Free transfers over 250 MB stay available for 7 days. Free transfers up to 250 MB stay available for up to 90 days. A larger backup needs SendGB Extra: 500 GB per transfer, 1 TB of storage, starting at €29.90 per year. SendGB Extra keeps files for up to 1 year. For a single image over 500 GB, SendGB Exceed is sufficient: no membership, €9.99 for a 1 TB transfer, and a code that can be used once and is valid for 1 year. The link stays available for 7 days. More than 1 TB will not fit in a single transfer.
Send a download link, not a disk image attachment
A small installation image may fit within 5 GB. Send a full disk backup up to 500 GB with SendGB Extra, or up to 1 TB in a single transfer with SendGB Exceed.
Start sending