通过电子邮件发送文件时的一个已知问题是附件大小的限制。通常，任何电子邮件服务都不允许发送大小超过几 MB 的文件。在尝试这样做时，电子邮件服务器可能会给出错误说明附件大小超出了允许的限制(The attachment size exceeds the allowable limit)或您附加的文件大于服务器允许的(The file you’re attaching is bigger that the server allows)大小- 或者电子邮件根本无法发送或接收。
缓解此问题的一种方法(One way to mitigate this problem)是在云驱动器上上传附件并通过电子邮件将链接发送给收件人。大多数云服务器允许免费上传最大 5-15 GB 的文件，所以这一定不是问题。
常见服务提供商的附件大小限制(Size Limits)
我们列出了以下服务的最大附件大小限制和文件大小：
- 微软展望
- Outlook.com
- 一个驱动器
- 办公室 365
- 邮箱
- 谷歌云端硬盘
- 雅虎
- 投递箱
- 推特
- Facebook
- WhatsApp。
1]微软展望
说到Outlook桌面客户端（不是电子邮件服务器），允许的最大附件大小为20 MB。这与使用的电子邮件服务器无关。如果电子邮件服务器允许其用户发送更大尺寸的附件，则它们可以通过其 Web 应用程序发送，但不能通过Outlook桌面或移动客户端发送。
如果您使用的是Exchange服务器，则限制可能会有所不同。通过Outlook客户端发送文件的附件大小限制可以修改，但发送文件的上限不能超过邮件服务器允许的大小。
阅读(Read)：修复附件大小超过 Outlook 上允许的限制(The attachment size exceeds the allowable limit )消息。
2] Outlook.com
Outlook/Hotmail允许发送的文件最大为10 MB，这要小得多。之后，用户可以将附件上传到OneDrive并发送链接。
3] OneDrive
它允许高达 5 GB 的免费存储空间和高达 50 GB 的付费存储空间。OneDrive的一个优点是它从Microsoft和其云驱动器上集成的Microsoft Office Online获得了支持。(Microsoft Office Online)
4]办公室365
Office 365 现在支持最大 150 MB 的电子邮件。
5] 邮箱
Gmail允许的最大附件大小为25 MB(25 MB)。与Gmail(Gmail)兼容的云驱动器 Web 应用程序是Google Drive。
6]谷歌驱动器
它允许免费存储多达15 GB的数据。付费计划可以帮助您购买高达 10 TB 的存储空间。
7]雅虎
雅虎也允许最大为25 MB的附件。之后，可以使用与Yahoo Mail兼容的Dropbox 链接(Dropbox links)发送更大尺寸的附件。
8] 保管箱
它提供高达5 GB的免费存储空间，并且可以购买其余计划。
9]推特
GIF、JPEG和PNG 照片(PNG Photos)最大可达 5MB；动画GIF(GIFs)在移动设备上最大为 5MB，在网络上最大为 15MB。视频文件(Video File)大小不应超过 15 MB（同步）或 512 MB（异步）。
10]脸书
通过Facebook消息发送文件(files)时，最大限制为25 MB。任何云盘链接都可以通过Facebook消息共享，但用户必须单独登录云盘的帐户。
对于在时间线上上传视频，每个文件的最大限制为(videos)1.75 GB和 45 分钟的运行时间。但是有一个限制：用户可以上传无限比特率的文件，只要文件的大小为 1 GB 或更小。当大小超过 1 GB 时，视频的比特率必须限制为 1080 高清文件的8 MBPS和 720 高清文件的 4 (MBPS)MBPS。
11] WhatsApp的
发送文件的附件大小限制为16 MB，可以增加到 30 MB。这要少得多，共享未压缩的视频变得非常困难。可以共享云驱动器链接，但链接在浏览器中打开，因此用户必须相应地登录。
每当通过云盘发送大文件时，接收方都需要使用同一云盘品牌的账号登录。例如。如果使用Hotmail帐户的用户向(Hotmail)Gmail用户发送 OneDrive 链接，则收件人可能无法访问该链接，具体取决于您的设置。
电子邮件服务提供商或社交网站可能会不时更改大小限制，因此请与您的服务提供商确认。
是否有任何我错过的重要电子邮件、文件共享或任何其他网络服务？如果是这样，请分享。(Is there any important email, files sharing or any other web service that I have missed? If so, pls do share.)
Attachment Size Limits for Outlook, Gmail, Yahoo, Hotmail, Facebook, WhatsApp
A known issue while sending files through email is the limit on the size of the attachments. Usually, any email service does not allow sending files larger than a few MB’s in size. On trying tо do the sаme, email serverѕ may give an еrror stating The attachment size exceeds the allowable limit or The file you’re attaching is bigger that the server allows – Or then the email simply won’t get sent or received.
One way to mitigate this problem is to upload attachments on cloud drives and send the link to the recipient through email. Most cloud servers allow uploading files up to 5-15 GB in size free of cost, so it must not be an issue.
Attachment Size Limits for common service providers
We have listed the maximum attachment size limits and sizes for files for the following services:
- Microsoft Outlook
- Outlook.com
- OneDrive
- Office 365
- Gmail
- Google Drive
- Yahoo
- Dropbox
- Twitter
- Facebook
- WhatsApp.
1] Microsoft Outlook
Speaking of the Outlook desktop client (not the email server), the maximum permitted attachment size is 20 MB. This is irrespective of the email server being used. If an email server allows its users to send attachments of larger sizes, they could be sent through their web application but not through the Outlook desktop or mobile client.
In case you are using an Exchange server, the limits might vary. The attachment size limit for sending files through the Outlook client can be modified, but the upper limit for sending the file cannot be more than that permitted by the email server.
Read: Fix The attachment size exceeds the allowable limit message on Outlook.
2] Outlook.com
Outlook/Hotmail allows sending files up to a maximum size of 10 MB which is quite less. After this, the user can upload attachments to OneDrive and send the link.
3] OneDrive
It permits free storage of up to 5 GB and paid storage of up to 50 GB. One positive with OneDrive is the support it gets from Microsoft and the integrated Microsoft Office Online on its cloud drive.
4] Office 365
Office 365 now supports email messages up to 150 MB.
5] Gmail
The maximum permitted attachment size for Gmail is 25 MB. The cloud drive web application compatible with Gmail is Google Drive.
6] Google Drive
It allows storing up to 15 GB of data for free. The paid plans could help you buy storage of up to 10 TB.
7] Yahoo
Yahoo permits attachments up to a size of 25 MB as well. After that, one could use Dropbox links compatible with Yahoo Mail to send attachments larger in size.
8] Dropbox
It provides free storage up to 5 GB, and the rest of the plans can be purchased.
9] Twitter
GIF, JPEG, and PNG Photos can be up to 5MB; animated GIFs can be up to 5MB on mobile, and up to 15MB on web. Video File size should not exceed 15 MB (sync) or 512 MB (async).
10] Facebook
When sending files through Facebook messages, the maximum limit is 25 MB. Any cloud drive link can be shared through Facebook messages, but the user has to be logged on to the cloud drive’s account separately.
For uploading videos on timelines, the maximum limit per file is 1.75 GB and 45 minutes of running time. But a restriction is as follows: A user can upload a file of unlimited bit-rate as far as the size of the file is 1 GB or less. When the size exceeds 1 GB, the bit-rate of the video must be limited to 8 MBPS for a 1080 HD file and 4 MBPS for a 720 HD file.
11] WhatsApp
The attachment size limit for sending files is 16 MB, and it could be increased to 30 MB. This is quite less and it becomes very difficult to share uncompressed videos. One can share cloud drive links, but the links open in the browser and thus the user has to be logged on accordingly.
Whenever sending large files through cloud drives, the receiver needs to be logged in from an account of the same cloud drive brand. Eg. If a user using a Hotmail account sends a OneDrive link to a Gmail user, the recipient may not be able to access the link – depending on your setting.
From time to time, the email service providers or social networking sites may change the size limits, so please do check with your service provider.
Is there any important email, files sharing or any other web service that I have missed? If so, pls do share.
